President Donald Trump ran on a campaign of America First, but so far, he has governed on Trump First—particularly when it comes to foreign policy. On no issue is that more apparent than his decision to formally recognize Jerusalem as Israel’s capital and set in motion plans to eventually move the U.S. embassy there from Tel Aviv.

“Today we finally acknowledge the obvious—that Jerusalem is Israel’s capital,” Trump declared Wednesday from the White House’s Diplomatic Reception Room, noting that the city is the seat of Israel’s government—home to its legislature, Supreme Court, and prime minister and presidential residences. But here’s another reality worth acknowledging: While other presidents have wanted to recognize Jerusalem as Israel’s capital, they knew that it needed to be done in the context of a final peace agreement with Palestinian consent; otherwise, it could incite violence, even, quite possibly, war. So why does Trump feel compelled to do this now?

After a difficult first year in office, with few accomplishments and more than a few scandals, Trump wanted to please evangelical supporters, who comprise much of his base, on an issue they care deeply about. “While previous presidents have made this a major campaign promise, they failed to deliver,” he said in his speech. “Today, I am delivering.” It was no accident that Vice President Pence, a hero to that constituency, stood by his side during his announcement, in a room adorned with Christmas decorations.

“Is he doing this because of domestic politics? I think there you’ve got a real possibility. Obviously, this is a president who has catered mostly to his base,” said Shibley Telhami, a Palestinian American scholar and professor at the University of Maryland. “This is a president who has shown, over and over, that he’s more interested in what’s good for Donald Trump.”

But with this decision, Trump is not exactly exemplifying the art of the diplomatic deal.