United Nations Ambassador Nikki Haley on Sunday said there was a key difference in Trump’s earlier opposition to taking action: He wasn’t in charge.

“He was worried about starting World War III over Syria. Why is that no longer a concern? And why was the 2013 chemical weapons attack, which, as you know, was deadlier, not a trigger for him in terms of the principle of inaction in Syria?” CNN’s Jake Tapper asked Haley.

“Well, he wasn’t president in 2013,” she said.

Haley said she couldn’t explain Trump’s earlier opposition.

“But I don’t know what his thought process was then,” she said. “I can tell you what his thought process was this week, which was, he is not going to condone chemical weapons use ever.

“I can tell you that of the conversations I had this week, he knew what the risks were, he knew what the situation was, he looked at the history of the situation, and he decided,” she added.

Haley’s comments left many unanswered questions about Trump’s dramatic reversal on the issue, and his apparent fickle foreign-policy decision making.

Trump in 2013 repeatedly warned Obama, whom he called “our very foolish leader,” not to intervene in Syria.

AGAIN, TO OUR VERY FOOLISH LEADER, DO NOT ATTACK SYRIA - IF YOU DO MANY VERY BAD THINGS WILL HAPPEN & FROM THAT FIGHT THE U.S. GETS NOTHING! — Donald J. Trump (@realDonaldTrump) September 5, 2013

President Obama, do not attack Syria. There is no upside and tremendous downside. Save your "powder" for another (and more important) day! — Donald J. Trump (@realDonaldTrump) September 7, 2013

During his presidential campaign, Trump ran on a stridently anti-interventionist platform. He argued that his opponent, Hillary Clinton, would start World War III over Syria.

Just last week, Trump said Assad’s regime in Syria would not be his foreign policy priority. But he said horrific images of Tuesday’s deadly chemical attack changed his mind. “Something should happen,” he said Thursday before the U.S. airstrikes.