President Trump announced on Wednesday that the United States would start the process of moving the U.S. embassy in Israel, which is currently located in Tel Aviv, to the city of Jerusalem. The move is a way to formally recognize Jerusalem as the Israeli capital, though that question has been at the heart of the Israel/Palestinian conflict for decades. Critics of the move see it as a barrier which will inflame tensions and make any kind of peace deal that much more difficult. Supporters point out that a peace deal seems nearly off the table as it stands, so why not lend some support to one of America’s only Middle East allies.

Here’s an excerpt video from the first two minutes of the President’s announcement:

In a his statement, President Trump said it’s “time to formally recognize Jerusalem as the capital of Israel.” The Wall Street Journal calls the move a gamble:

“We will move the American Embassy to the eternal capital of the Jewish people, Jerusalem,” Mr. Trump told the American Israel Public Affairs Committee, one of the largest pro-Israel groups in the U.S. in March 2016, when he was the front-runner for the Republican presidential nomination. AIPAC struck a positive tone on Mr. Trump’s decision, tweeting: “It is our long-held position that undivided #Jerusalem is the historic, current and future capital of Israel. We continue to believe that the United States should recognize Jerusalem as Israel’s capital.”

Arab leaders across the Middle East are making last-ditch appeals to the U.S. not to declare Jerusalem as Isreal’s capital. The foreign ministers of Jordan and Egypt have called Secretary of State Rex Tillerson to warn about the dangers of such an announcement. Palestinian leaders had pledged to stop working with the U.S. if Mr. Trump makes any declaration about Jerusalem this week. And Americans have been warned to carefully consider travel plans to Jerusalem’s Old City and the West Bank, citing widespread calls for demonstrations to be held today.

Mr. Trump’s decision on Jerusalem marks a return toward unilateral action after his frustrating year working with Congress, where the push to the repeal the Affordable Care Act stalled and the tax reform effort, which isn’t finished, has yielded changes to the tax code that are unpopular with the public.

The current embassy was opened in 1966 in Tel Aviv, over the objections of Israel which claimed Jerusalem as the capital. The Tel Aviv location became a compromise so that formal relations with the Israel state could begin while the United States attempted to avoid getting entangled in the regional conflict between Israelis and Palestinians.

Among lawmakers in Congress, Republicans heavily favor the move. On the Democratic side, however, the reactions are mixed, according to The Weekly Standard:

Sen. Schumer in October called on Trump to move the U.S. Embassy and argued that doing so would “show the world that the U.S. definitively acknowledges Jerusalem as Israel’s capital.”

Maryland senator Ben Cardin, the top Democrat on the Foreign Relations Committee, reiterated his support for recognizing Jerusalem when asked Monday about the president’s potential announcement.

“I believe that Jerusalem is the capital of Israel, so to me, that’s not news,” he told TWS. Cardin added that Trump needs to make that announcement “in a way that advances Israel’s security and peace in the region.”

But a number of other Democrats are worried that Trump’s recognition of Jerusalem could undermine potential peace negotiations and trigger violence.

New Jersey senator Cory Booker said both the capital and embassy issues should be “part of a larger peace process.”

“It should be part of negotiations for eventual final status,” Booker told TWS. “We need to be working towards peace in that region.”

California senator Dianne Feinstein wrote to Trump on Friday warning him that declaring Jerusalem the capital would “undermine any remaining hope for a two-state solution.”

As a direct result of the move, Turkey’s president is calling for an “Islamic Summit” to address the matter, according to France24:

Turkish President Recep Tayyip Erdogan is calling a summit of the main pan-Islamic body in Istanbul on December 13 to discuss the expected US move to recognise Jerusalem as Israel’s capital, his spokesman said on Wednesday.

“In the face of developments that arouse sensitivity over the status of Jerusalem, Mr President is calling a leaders’ summit of the Organisation of Islamic Cooperation (OIC) in order to display joint action among Islamic countries,” presidential spokesman Ibrahim Kalin told reporters in Ankara.

He said the summit meeting would take place on December 13. There was no immediate confirmation from Muslim leaders if they would come.

Israeli Prime Minister Benjamin Netanyahu praised the decision, according to Haaretz:

Prime Minister Benjamin Netanyahu said Wednesday that Israel’s “historical and national identity is receiving important expressions every day, but especially today.” The prime minister was speaking in a Facebook video ahead of the expected announcement by U.S. President Donald Trump to recognize Jerusalem as Israel’s capital. 

The move will ultimately take several years to complete. Embassies just don’t pack up and move overnight. The first step will be identifying actual land in Jerusalem, then going through a lengthy construction phase. The new embassy will need to be heavily fortified, of course, and all of this will take some time.

In fact, it’s entirely possible that this could bleed into another administration depending on whether Donald Trump wins reelection in 2020. While it’s probably unlikely that a different president would reverse this course, since it does have bipartisan backing, it’s possible that it could be further delayed depending on the circumstances.