President Donald Trump’s acceptance of Beijing’s demand that he re-commit to a “one China” policy was heavily influenced by his new top diplomat, who argued behind the scenes that relations would remain on hold until Trump cleared up doubts about a longtime bedrock of U.S.-China ties, officials said.

The abrupt course adjustment, made public in a White House statement on Thursday after a phone call between Trump and Chinese President Xi Jinping, followed White House meetings this week involving Secretary of State Rex Tillerson, the U.S. officials said, speaking on condition of anonymity.

Tillerson joined Trump’s national security adviser Michael Flynn and others in what one administration official described as a concerted effort to persuade the president that “this is the right way to go, this is right for the relationships and regional stability – and they won the day.”