Republican leaders on Wednesday proposed slashing tax rates for the wealthy, the middle class and businesses while preserving popular tax deductions that encourage buying homes and giving to charity, hoping to unify the party behind a proposal to revamp the U.S. tax code.

But the nine-page framework they released to kick off negotiations left many key questions unanswered, including how they plan to avoid adding trillions of dollars to the government’s debt. The framework leaned heavily on limiting taxes paid by the wealthiest Americans, such as the alternative-minimum tax, and opposition to these changes from Democrats suggest it will be a battleground as negotiations intensify.

Republicans were also careful not to identify numerous tax breaks they might remove, focusing instead on promises to lower rates so much that President Trump estimated the effort would amount to the biggest tax cut of all time.

The “unified framework” was meant to serve as a starting point for negotiations on a tax deal, which lawmakers hope to complete by the end of the year. Republican leaders are now tasked with resolving controversial questions to unite their party — and possibly some Democrats — behind tax legislation, such as what corporate tax breaks to protect and how much revenue they are willing to lose in pursuit of new economic growth.

Trump has made rewriting the tax code a major part of his domestic agenda, and on Wednesday he urged his party on.

Which tax breaks are for you? View Graphic Which tax breaks are for you?

“This is a once-in-a-generation opportunity, and I guess it’s probably something you could say I’m very good at,” Trump said in Indiana. “I’ve been waiting for this for a long time.”

The Committee for a Responsible Federal Budget estimated that the nine-page framework would equate to a $2.2 trillion tax cut, with $5.8 trillion lost to lower rates and other changes, and another $3.6 trillion recouped by eliminating deductions.

There were few initial estimates of what the tax framework might mean for economic growth, an area that will likely divide Republicans supportive of the plan and Democrats who immediately complained that the changes would disproportionately benefit the wealthy.

The White House and GOP leaders negotiated for months and agreed in large part only on the taxes they want to cut. They now face the more arduous task of agreeing on which tax deductions to take away, a process sure to pit party members against each other and put them under extreme pressure from outside lobby groups fighting to protect their favored tax breaks.

“I hope that people will have the intestinal fortitude it’s going to take to do it right,” Sen. Bob Corker (R-Tenn.) said late Tuesday. “People say the health care was hard — you have no idea. You have no idea how this is going to be.”

[The GOP tax plan, explained in simplest possible terms]

In Indiana, Trump threatened to try to oust Democrats who don’t vote to help push the tax cuts into law. He singled out Sen. Joe Donnelly (D-Ind.), who is up for reelection next year, as a Democrat who would be targeted if he didn’t sign onto the GOP plan.

“We will come here, we will campaign against him like you wouldn’t believe,” Trump said.

Democratic leaders will try to keep their party united in opposition, and on Wednesday they charged the GOP with proposing a huge tax cut to the wealthy but offering little for anyone else.

They said there was little evidence the tax plan provided any tax relief for low-income Americans, and it couldn’t be learned how much the middle class would benefit, either. Republicans didn’t specify what tax rates would apply to certain income levels, making it also hard to determine the framework’s impact.

“Republicans’ tax framework is not tax reform,” said House Minority Leader Nancy Pelosi (D-Calif.). “It is a framework that gives away the store to the wealthiest while sticking the middle class with the bill.”

Without Democratic support, Republicans would need near-universal backing from their own party to move a tax bill through Congress, especially in the Senate, where they hold a slim majority.

In their blueprint, Republican proposals include cutting the corporate tax rate from 35 percent to 20 percent and making it much easier for multinational companies to bring money earned overseas into the United States. This is roughly in line with a long-standing House Republican goal, though Trump has consistently pushed for the corporate rate to be lowered to 15 percent.

They also propose collapsing the seven individual income-tax brackets into three and allowing more people to qualify for the Child Tax Credit, designed to help low-income working families.

The framework would roughly double the standard deduction that married families and individuals use to reduce their taxable income, a change that Republicans hope will simplify the filing system. But it would also eliminate the “personal exemption” taxpayers can claim, blunting much of the new benefit and potentially leading some middle class households with multiple family members to pay more taxes than they currently do.

[Some tax breaks are for the rich. Others for the poor. Which are for you?]

Republicans also are holding out the possibility of imposing a new, higher tax rate on the wealthy to ensure that the tax changes do not disadvantage the middle class, though the White House and GOP leaders have not agreed on how that would work.

Many of the tax changes would benefit upper-income Americans. The Republicans propose eliminating the estate tax and the alternative minimum tax. They also proposed lowering taxes on investment income. The tax framework does not mention Trump’s long-standing promise of raising taxes for hedge fund managers, suggesting that differences on this point have not been resolved.

While the blueprint preserves tax breaks for mortgage interest and charitable contributions, it proposes changing the tax benefits for retirement and education. It is unclear how those changes might work.

The next step for congressional Republicans is to pass a budget resolution that would allow a tax bill to pass the Senate with a 51-vote majority. Senate bills often need 60 votes to overcome a filibuster, but the budget resolution would allow Republicans to use the process known as “reconciliation” to avoid that higher threshold.

Sen. Patrick J. Toomey (R-Pa.) said Wednesday the Senate Budget Committee is expected to send a draft budget to the Senate floor next week.

The House Freedom Caucus, a key holdout bloc of conservative lawmakers, endorsed the tax framework Wednesday, setting up a floor vote on the House budget as soon as next week. That would set up a conference between the chambers, with senior Republicans expecting the final, consensus budget resolution to closely resemble the Senate version.

Once the budget resolution passes both chambers, the tax-writing committees — Senate Finance and House Ways and Means — would begin drafting and amending tax legislation, where the politically thorny work of identifying revenue offsets would take place.

Toomey acknowledged that hard trade-offs are ahead, saying that lawmakers will have to identify offsets of about $3 trillion over 10 years to align the plan with the budget resolution.

The framework released Wednesday calls for eliminating many business tax credits and individual income deductions, while specifically naming only a few that should be spared.

“We’ve definitely identified the items that can get us there,” Toomey said. “The question is: Will we have the political will to do it?”

To raise revenue to offset the cuts, Republicans are likely to consider limiting or eliminating the deductibility of state and local taxes, a proposal that is generating opposition from lawmakers in states with high tax burdens. They will also consider limits on how much businesses can deduct for interest payments, a tax provision frequently used by financial and real estate firms.

“Those are two big ones that have to be on the table,” Toomey said.

Business groups, who have already been leaning heavily on lawmakers to protect their favored tax breaks, had mixed reactions to the plan. Many cheered the general direction of the plan but made clear they were watching how Congress approached key unresolved details.

“Now, we are entering into a crucial new phase of the effort to overhaul the tax code, and the hardest work is just beginning,” U.S. Chamber of Commerce President Thomas J. Donohue said in a statement. House Ways and Means Committee chairman Kevin Brady (R-Tex.) will visit the Chamber on Thursday to discuss the plan.

Koch Industries sent an open letter to Congress, praising members for moving forward on the tax changes but encouraging lawmakers to cut as many business-specific tax breaks as possible.

“We encourage policymakers to remove corporate welfare provisions from the code. Wherever possible, loopholes, deductions, exemptions and other handouts should disappear. We maintain that cutting rates is the most reliable pathway to growth,” wrote Philip Ellender, president of government and public affairs at Koch Companies Public Sector.

Other industry groups outlined specific concerns.

The National Association of Realtors denounced the blueprint, saying in a statement Wednesday that the proposal to double the standard deduction would “all but nullify the incentive to purchase a home” for most taxpayers. With the standard deduction doubling, more homeowners would probably use that deduction when they filed their tax returns, rather than taking advantage of the lucrative mortgage interest deduction.

“This proposal recommends a backdoor elimination of the mortgage interest deduction for all but the top 5 percent who would still itemize their deductions,” William E. Brown, president of the National Association of Realtors, said in a statement. “Plummeting home values are a poor housewarming gift for recent homebuyers and a tremendous blow to older Americans who depend on their home to provide a nest egg for retirement.”

Jim Tobin, the chief lobbyist for the National Association of Home Builders, said his organization was encouraged to see many of its top priorities included, including access to interest deductions and the preservation of the low-income housing credit.

He said his organization, like that of the Realtors, was concerned about doubling the standard deduction and about losing the deduction for state and local taxes.

“We also recognize we’re in the opening stages of what is going to be a long fight, a long journey, to realize tax reform — so as the opening play in this, we feel good about continuing to move forward,” Tobin said.

Dozens of Georgetown University students gathered Tuesday on the steps of McDonough Hall to protest an address from Attorney General Jeff Sessions that lambasted schools for infringing on students’ free-speech rights.

The students were joined by faculty members who initially took a knee and later linked arms.

They took turns speaking into a bullhorn, decrying Sessions, the process the university used to bring him to campus and posing questions they would have asked the attorney general had they been allowed into the event.

“We, the disinvited, find it extraordinarily hypocritical that AG Sessions would lecture future attorneys about free speech on campus while excluding the wider student body,” third-year law student Ambur Smith said into the bullhorn.

Some of the roughly 100 protesters who gathered outside at Georgetown’s law school wore duct tape over their mouths. They held signs that proclaimed, “DEPORT HATE,” FREE SPEECH IS NOT HATE SPEECH,” and “Sessions is afraid of questions.”

Georgetown law professor Heidi Li Feldman was one of about 40 faculty and staff members who joined students on the steps of McDonough Hall.

“A law school is a place for people to learn about the deepest principles that undergird our democratic republic. Those principles are trampled upon by Attorney General sessions, in particular, and Donald Trump,” she said. “You cannot invite people who so thoroughly threaten the basic premises of American law to a campus and not speak up if your mission in life is to educate people about the American legal system.”

Third-year law student Imani Waweru cited President Trump’s criticism of NFL players and other actions by the White House in asserting that the administration  “has fallen short in a lot of areas about understanding what free speech entails.”

“We just firmly believe that this administration does not demonstrate that they have a full understanding of free speech,” Waweru said.

By 12:20 p.m., the crowd of demonstrators had thinned to about half its earlier size.

Inside the hall where Sessions spoke, a line of attendees sitting near the back stood up as the attorney general concluded his address. The group sat back down, and had tape over their mouths.

Greyson Wallis, a Georgetown law student from Bradenton, Fla., was among those who demonstrated up after Sessions delivered his remarks. She said that though Sessions is a controversial figure, that wasn’t the main reason for the protest. Wallis, 24, said Georgetown students signed up for the event, but were then told via email their invitations had been rescinded.

“It seemed like they were rescinding those invites because they didn’t want any sort of hostile environment, and I can understand not wanting to have a violent environment, but that’s not at all what we were trying to do,” Wallis said. “We’re law students. We all just wanted to hear what he had to say and let him know where we differ from his opinions.”

Wallis, who wore a black toque that read “nasty woman,” said she felt Sessions gave a speech to an “echo chamber,” a group of people who agree with his policies and stances.

“This was at no point at risk of turning into Berkeley in any manner,” she said, referring to violent protests earlier this year in the California city. “But people wanted to be here and hear what he had to say. Unfortunately, his message of opening yourself up to the other side isn’t going to reach the people that he wants it to reach. Because they weren’t allowed to be in here today.”

Joshua Spielman, 29, a Georgetown law student in the audience, said he agreed with what Sessions told the crowd Tuesday, and said he felt it was important for the university to “uphold the values of allowing all speech.”

“I find that there are students who believe themselves to be in the ideological majority without understanding that there may be students who want to hear a free flow of ideas,” he said. “But that doesn’t necessarily mean they agree with everything that the administration has to say. And I think it’s important as a university for us to ensure that all ideas are heard. Because if you don’t hear all ideas, then correctly, as the attorney general said, you can’t possibly formulate your own.”

Spielman, of Teaneck, N.J, said he would be considered a “more conservative” student on campus, then added: “but that doesn’t mean I’m a conservative.”

“There may be policies within the Trump administration that I agree with, that doesn’t mean I condone the president’s behavior and the way he seeks to vocalize his opinions or the administration’s stances,” he said. “That doesn’t mean there aren’t components of his administration’s polices that I don’t agree with. But what I find to be a major problem to be on campus, here and around the country, is that if you express any semblance of agreement with any variation or even piece or kernel of any of those policies, you’re immediately labeled as someone who is on the poles of one side or another.”

The attorney general’s address on free speech at the Georgetown’s Law Center sparked a variety of responses in advance from students and faculty members.

Some welcomed the opportunity to hear from the top law-enforcement officer and top lawyer in the U.S. government. But others objected to the late notice and limited audience for such a high-profile speaker, and argued that was antithetical to the idea of free speech and an open exchange of ideas.

Sessions, who has sparked controversy over immigration, race and other issues, planned to talk about free speech on college campuses. It’s a fraught topic nationally, with many conservatives saying that only liberal viewpoints are welcome on many college campuses, stifling free exchange and overly sensitive students finding alternative viewpoints too offensive to hear.

On Monday, some students said they got messages informing them they would not be allowed to attend the event, as they were not included on the invitation list drawn up by the Georgetown Center for the Constitution at Georgetown Law, which is hosting Sessions.

More than 130 students who had followed official channels to register for a seat in the auditorium were told they could attend, Lauren Phillips, a student at the school, wrote in an email Monday night. But the students were later suddenly uninvited because they were not part of a group that, Phillips believes, would ensure a sympathetic audience.

She said those students “find it extraordinarily hypocritical that AG Sessions would lecture future attorneys about the importance of free speech on campus while actively excluding the wider student body,” and that school officials had told students they could voice their objections only within a designated “free speech zone” which she said was a tiny, isolated corner of the campus. “We hope in the future that the university will truly uphold the principles of free speech, including the right to dissent.”

Tanya Weinberg, a spokeswoman for Georgetown’s law school, disputed the notion of a free speech zone.

“Free speech is protected for students on campus; there is no particular zone,” Weinberg said. “At events like today’s, we designate protest areas to allow free expression on campus in a manner that upholds safety and security and minimizes potential disruptions to learning.  Additionally, students in the auditorium were allowed to protest in a way that did not disrupt the event.”

Sessions spoke at a university that publicly objected earlier this month to the Trump administration’s move to end the Deferred Action for Childhood Arrivals program, and includes several faculty members who are high-profile opponents of administration policies such as Neal Katyal, one of the lawyers challenging the travel ban.

Several students said they would have liked to have had the opportunity to ask questions about administration policies — especially about the topic of free speech.

It’s ironic, said Spencer McManus, a third-year student from California, “that this attorney general is coming to our campus to tell us to exercise our constitutional rights, when he and the president have repeatedly condemned those who have exercised those rights. … We want people to understand what the First Amendment means.”

Over the weekend, President Trump condemned NFL players who sat out or took a knee during the national anthem before games in protest, saying they should be fired.

After unexpectedly violent protests forced the shutdown of a speech by provocative writer Milo Yiannopoulos at the University of California at Berkeley in February, Trump suggested that federal funding should be withheld if a state flagship school couldn’t tolerate free speech.

Berkeley has been the most visible flash point, but similar philosophical fights have played out at many other campuses as well.

Many people are critical of the idea of campuses giving students “safe spaces” and “trigger warnings” to protect them from ideas that they find offensive or upsetting.

“Holding an event that creates a safe space for the attorney general — and such a safe space that you don’t even invite people who commit to not disrupt the event while it’s ongoing — demonstrates a certain amount of hypocrisy,” said Heidi Li Feldman, a professor at the law school who said she had been denied permission to attend.

“To invite somebody who purports to be an authority  on free speech who so profoundly misunderstands the theories and law of free speech in our country … is laughable,” she said.

Some faculty members issued a statement Monday night, saying they acknowledge his right to speak on campus but “condemn the hypocrisy of Attorney General Sessions speaking about free speech.”

Feldman said some professors would protest — not by blocking or disrupting the event, but by expressing their opinions.

Richard Hand, a third-year student, said: “In law school, I’ve learned the most from my colleagues who have different opinions than me. I’ve also seen that people can disagree without disrespecting or insulting each other. I’m sure the attorney general and president would be welcome to sit in on a class.”

Some objected to Sessions himself, and his views.

“No fascists on campus,” a student wrote in an online forum planning protests. “A university that claims to care about the travel ban and DACA rescindment shouldn’t invite the man who defended both. Bring any signs and banners you can …”

Some objected only to the way the audience was drawn up.

The event was hosted by a center at the school, and they handled the invitations, according to a law school spokeswoman.

The invitations were issued in the same way they typically are, Tanya Weinberg said, without an attempt to assure an ideologically sympathetic crowd. Given limited capacity, she said, the school’s policy has held that the hosting organization determines the guest list. In this case, the Center for the Constitution decided to invite students who have attended past events held by the center, and Barnett invited students from his classes.

Scholars at the center are invited, she said, along with some “personal/VIP” guests invited by the center and the Justice Department.

Some students expressed dismay that their own invitations seemed to be revoked as the day went on, with many sharing a message they had received: “You RSVP’d earlier today to an invitation to hear Attorney General Jeff Sessions, sponsored by the Center for the Constitution. Regrettably, the email you subsequently received indicating you have a seat for the event was in error. Our records indicate that you were not part of the Center’s student invitation list, which includes student fellows of the Center (students who signed up to attend events sponsored by the Center) and students enrolled in the classes taught this semester by the Center’s Director, Professor Randy Barnett. As stated in the initial invitation email, the invitation was non-transferable and intended only for the individual to whom it was sent. Unfortunately, we will not be able to offer you a seat for the event.

“We regret any inconvenience.”

Phillips, who said she was one of the students who received such a message, said that if they had been allowed to attend, they would have asked questions about the Trump administration’s policies on criminal justice. She also wanted answers on why the issue of private citizens protesting during the national anthem before NFL games seemed to demand more of Trump’s attention recently than other pressing issues, and why the Trump administration seems more critical of student demonstrations on campus than white-supremacist rallies.

She said they would gather outside before the speech, bringing their questions for Sessions.

Statement by some faculty members: