Last April, the Trump administration launched strikes on a Syrian-government airfield in retaliation for a brutal chemical attack on the town of Khan Sheikhoun.

Standing alongside Jordan’s King Abdullah II last year, Trump said that the chemical attack on Khan Sheikhoun crossed “a lot of lines for me.”

“When you kill innocent children, innocent babies, little babies with a chemical gas that is so lethal that people were shocked to hear what gas it was, that crosses many lines beyond the red line. Many, many lines,” he said.

Late Sunday, reports emerged of airstrikes at an airport in the Syrian city of Homs, leading many to believe that Trump had once again called for retaliation. However, the Pentagon was quick to dismiss the reports, saying the airstrikes were not conducted by the U.S. The Russian defense ministry said Monday that two Israeli F-15 jets were behind the strikes.

Where carefully crafted policies ideally precede public messaging, advisers now often scramble to reshape policy to catch up with the president’s tweets and public declarations.

Trump’s tendency to tweet his mind has blindsided advisers and, in some cases, complicated or even upended administration policy.

Bolton’s predecessor, Gen. H.R. McMaster, told participants at an international security conference in Germany in February that “the evidence is now incontrovertible” that Russia interfered in the U.S. presidential election.

Trump quickly — and publicly — called McMaster out for what he viewed as an incomplete message.

“General McMaster forgot to say that the results of the 2016 election were not impacted or changed by the Russians and that the only Collusion was between Russia and Crooked H, the DNC and the Dems,” Trump tweeted. “Remember the Dirty Dossier, Uranium, Speeches, Emails and the Podesta Company!”

Bolton, who is also skeptical of Moscow, takes on the delicate balancing act of responding forcefully to Russian aggression around the world, while appeasing the president’s stated interest in warmer ties with Russia’s President Vladimir Putin or his efforts to defend the outcome of the U.S. presidential election.

But his most pressing task, as he met with other White House National Security Council principals after just hours on the job: helping to hammer out Syrian response options for a president who, just days ago, publicly pined for a speedy exit.