Initially, the president was hesitant to believe the intelligence that Russia was behind the attack — a fact that some aides attributed to his contrarian personality and tendency to look for deeper conspiracies. To persuade him, his advisers warned that he would get hammered in the press if he was out of step with U.S. allies, officials said.

“There was a sense that we couldn’t be the only ones not to concede to reality,” the Trump adviser said.

The next task was convincing Trump that he should punish Putin in coordination with the Europeans. “Why are you asking me to do this?” Trump asked in a call with British Prime Minister Theresa May, according to a senior White House official. “What’s Germany going to do? What about France?”

He was insistent that the poisoning in the English city of Salisbury was largely a European problem and that the allies should take the lead in moving against Russia.