As with a number of things that have outraged many outside the White House, it all started with a campaign promise.
Administration officials had refused to confirm the announcement until the day before Mr Trump took to the podium in the Diplomatic Reception Room of the White House, despite numerous reports.
Condemnation, which had become a running theme during the previous few days, came in a torrent after Mr Trump had spoken. Fittingly, it was diplomacy that many other world leaders had worried about – with Mr Trump seeking to overturn decades of American foreign policy by declaring Jerusalem the capital of Israel in addition to the embassy move.
Leaders from the region and beyond can rightly wring their hands in anxiety at the thought of protests – and potential violence – as well as progress lost in a peace process that was already looking difficult. There appears to be little immediate political gain for Mr Trump, seemingly the one reason to upset the balance of one of the most thorny issues in world affairs, but to Mr Trump that seems to matter little.
Two of the things the President built his run to the White House on are being different from the political status quo, and the number of definitive promises he made to his base. Some of those, such as the border wall with Mexico and the repeal of Obamacare rely on many others, and some have floundered. But here was a decision that he could make alone and nobody could say Mr Trump does not have the confidence to believe his way is right.
Donald Trump officially recognises Jerusalem as Israel’s capital
It is an easy win for Mr Trump in terms of his supporters, and keeping his word, but also sets him at odds with previous presidents – a place he likes to be. While he signed a new six-month waiver deferring the moving of the US embassy – as every president has done since Congress passed a measure mandating the move in 1995 – he made clear that the waivers didn’t work. He portrayed himself as the man that would be the one to take the step his predecessors couldn’t, even if some of them supported the move before making it into the White House.
That reticence of previous presidents is a pointer of the difficulties that persist over Jerusalem and its place as part of a larger peace accord. But Mr Trump may also believe that he can use such a dramatic change to bring about that peace between Israel and the Palestinians.
The fact that the President sought to reassure the Palestinians and other nations in the region that he was not trying to declare a final decision on the status of Jerusalem’s disputed borders would suggest that his advisers had made clear that such a radical shift in policy needed some nuance. And that bigger difficulties – bringing the Palestinians back to the table in the wake of the announcement – lie ahead. Meanwhile, the fact that almost every other nation bar Israel condemned the move to various degrees shows that Mr Trump may have bitten off more than he can chew.
Mr Trump has always said that he would back himself to make a deal. But it is a massive – and seemingly ill-advised gamble – that has the potential to cause suffering for a great many without tangible reward.