This implies that the United States is increasingly supportive of Israel’s position — full annexation — though this would almost certainly kill any viable peace deal.
Why Does It Matter if the U.S. Takes Sides?
The United States has, for decades, positioned itself as the primary mediator between Israelis and Palestinians. Neutrality ostensibly allows the United States to remain a credible arbiter and keeps both sides at the negotiating table.
American diplomats tend to consider neutrality a bedrock principle and essential for peace, and see Mr. Trump’s announcement as an alarming break.
But the policy of neutrality has grown contentious in American politics since the 1980s and the rise of the evangelical Christian right as a political force.
The movement’s pro-Israel positions — strongly in favour of Israeli control of Jerusalem — have roots in millenarian theology as well as more straightforward identity politics. (Still, a number of Palestinians are themselves Christian, and Jerusalem’s Christian leaders objected to Mr. Trump’s move.)
Evangelical Christians have been joined by a subset of American Jews and others on the political right in arguing that the United States should overtly back Israel in the conflict. This position hardened during the second intifada, a period of vicious Israeli-Palestinian conflict in the early 2000s.
This debate has often played out over Jerusalem. Presidential candidates will promise to move the American Embassy from Tel Aviv to Jerusalem, thereby recognizing the city as Israel’s capital. But once in office, the new president will forestall the move, explaining that peace should be given a chance.
Mr. Trump actually went ahead (though only partly, because he will not move the embassy right away), implicitly endorsing an American shift from neutral arbiter to overtly siding with Israel.
Has the U.S. Really Been Neutral?
That is not really the perception outside of the United States, particularly in Europe and the rest of the Middle East.
Much of the world already considered the United States a biased and unhelpful actor, promoting Israeli interests in a way that perpetuated the conflict.
Partly this is because of the power imbalance between Israelis and Palestinians. Because the far stronger Israelis are the occupiers, and the United States is seen as a steward for the conflict, the Americans are sometimes blamed, rightly or wrongly, for that imbalance.
Partly it is because of domestic politics that led American leaders to pronounce themselves as pro-Israel while pursuing policies intended as neutral.
But it is also because of a decades-old American negotiating tactic. The last three administrations — led by Bill Clinton, George W. Bush and Barack Obama — all believed that they needed to grant Israel concessions to make Israeli leaders feel secure and comfortable enough to make their own concessions for peace.
So Mr. Trump’s move, though he does not describe it this way, is arguably in line with past American strategy. And it is seen abroad as confirming long-held doubts about American leadership, rather than as drastically new.
What Happens Now?
Protests, which sometimes grow violent, have been a common Palestiniananswer to perceived provocations, particularly on issues related to Jerusalem. The Palestinian view is that Israel’s occupation should be made costly and uncomfortable if it is to ever end.
As for the wider Arab response, the United States is just not very popular or trusted in the region. That tends to happen when you invade an Arab-majority country, Iraq, on what most Arabs consider false pretences, starting a war that kills hundreds of thousands. This move is going to be unpopular, but it’s sort of a drop in the bucket.
Still, it could complicate regional politics. Marc Lynch, a political scientist at George Washington University, wrote in The Washington Post,
“The visible pursuit of peace, if not its achievement, has long been the mechanism by which the United States reconciles its alliances with Israel and with ostensibly anti-Israel Arab states.”
This could make it harder for Arab governments to justify their cooperation with what is perceived to be an American-Israeli plot against Palestinians. Even if Arab governments do not themselves care much about Palestinians, they worry about domestic unrest.
That doesn’t mean Arab states will break with Washington, but they might need to be a little quieter and more careful about cooperating.
What Does This Change Long Term?
Warnings of a long-term shift tend to hinge on the idea that losing American neutrality means losing American leverage over Israelis and Palestinians to achieve peace.
But the simple fact of American power makes the country an important broker, neutral or not. American leverage with Israel also comes from implicitly guaranteeing Israel’s security and providing it with lots of military hardware. Still, because Israel got something for nothing from Mr. Trump’s announcement, it has little reason to make difficult concessions.
American leverage over Palestinian leaders is also significant, since those leaders rely on American support to keep their administration funded and stable. But those leaders are deeply unpopular with their own people. A real risk here is that they one day grow so unpopular that their administration collapses. This would risk chaos and violence in the short term and, long term, a likely takeover by the militant Palestinian group Hamas.
All of that points toward a future in which peace is less likely, a Palestinian state is less likely and Israel is one day forced to choose between the two core components of its national identity: Jewish and democratic. Either it asserts permanent control over Palestinians without granting them full rights — a sort of state that critics sometimes compare to apartheid South Africa — or it grants Palestinians full rights, establishing a pluralistic democracy that is no longer officially Jewish.
Mr. Trump’s move likely edges Israelis and Palestinians closer to that future. But things were probably moving in that direction already.