It is almost impossible to see the logic of the Trump administration’s expected recognition of Jerusalem as Israel’s capital, and possibly moving the U.S. embassy to Israel there—before it even unveils what’s certain to be a controversial plan for Middle East peace, which will be tough enough to sell.

The White House is probably betting that, despite the noises in the Arab world against such a move, their key allies in Saudi Arabia and Egypt will limit their opposition—already publicly voiced—to lip service, as they are all interested in protecting relations with Trump over more urgent issues, such as fighting militancy and confronting Iran. It’s also betting that the Arab and Muslim public outcry will be limited, both because of efforts by their governments to contain dissent, and because administration officials may have swallowed the arguments that Arabs no longer care about Palestine, or even Jerusalem.

All of this is doubtful, but let’s consider for a moment the possibility that the administration’s assessment that costs will be limited is accurate. No one, not even President Donald Trump, is arguing that such a move would be helpful to American Middle East policy. This begs the question: Why is Trump doing this?

Trump certainly doesn’t need to solidify his pro-Israel credentials; three of his key Middle East advisers are known to be sympathetic with the Israeli right. More importantly, the American public, including his Republican core, already thinks his policy is pro-Israel. A University of Maryland Critical Issues Poll (among a national sample of 2,000 American adults, fielded by Nielsen Scarborough November 1-6 and released at the Brookings Institution last Friday) found that 59 percent of Americans said they preferred that Trump lean toward neither side of the Israeli-Palestinian conflict. In contrast, 57 percent of Americans, including most Republicans, said he is in fact leaning toward Israel. Our poll also shows that 63 percent of all Americans oppose moving the U.S. embassy in Israel to Jerusalem, including 44 percent of Republicans.

How about the Evangelical Christians whose support has been critical for Trump, and who are known to support declaring Jerusalem as Israel’s capital and moving the U.S. embassy there? Two-thirds of Evangelicals say Trump’s policy is already leaning toward Israel—a proportion that’s even higher than that of the rest of the population. Even on moving the U.S. embassy to Jerusalem, the support is hardly overwhelming: While 53 percent of Evangelicals support the move, 40 percent oppose it.

Evangelical leaders undoubtedly bring this issue up with the president, but none will abandon him for not making the declaration. Trump has been the president who has arguably given the Evangelical right more than any other president in history has: from favorable key appointments such as Supreme Court Justice Neil Gorsuch and Secretary of Education Betsy DeVos, to highly favorable policies toward religious schools.

In the meantime, the administration’s assumptions about the limited costs of the move are based on little more than a leap of faith. In fact, the move would go against the very priorities that the administration has set for itself in the Middle East: fighting Islamist militancy and confronting Iranian influence. Jerusalem is the perfect issue for Iran and Islamist militants to use to mobilize support against the United States and those who endorse its policies.

Publicity over likely limited Arab voices, such as the Twitter hashtag, #Riyadh-is-more-important-than-Al-Quds, may have played a role in the assessment—in addition to re-enforcing Israeli government statements. But this is not new. In the lead-up to the Camp David negotiations that President Bill Clinton mediated in 2000, it was not hard to see that the White House underestimated the centrality of Jerusalem to the Palestinians and Arabs broadly (see here and here, for instance) and that this issue could bring the negotiations down. It did.

Sure, the Middle East is more divided today than it was then. Many Arabs are focused on their immediate tragedies; others may have a diminished connection to Palestine, or even to Jerusalem. But as the region has grown deeply divided, Jerusalem has remained a central symbol that transcends the divide. It remains a mobilizing issue even in a polarized environment: Even if Arabs don’t go out into the streets in consequential numbers, a declaration will play into the hands of those plotting in the basement.

It’s also good to recall what happened just a few months ago, as the same assumptions about the irrelevance of Palestine and Jerusalem prevailed. Following the killings of Israeli policemen, an Israeli government attempt to install security machines to search Palestinian worshippers at al-Aqsa Mosque generated Palestinian demonstrations that quickly mobilized Arab and Muslim public opinion, and led to intervention by governments—ultimately forcing a reversal of the measures.

There is of course a direct impact on Jordan, whose stability is essential; King Abdullah, an American ally, has been among the first to make clear in his warnings about the impact of the move on his society; since then many have added their warnings including Turkish and French leaders, among others. Then, there is the direct impact on the Palestinians. The move could force Palestinian President Mahmoud Abbas to walk away, at least initially, from talks. But even if Trump could get Abbas to swallow the move, the leverage Abbas would expend to keep any degree of legitimacy among Palestinians will inevitably come at the expense of his ability to convince the Palestinians to swallow any deal Trump will offer—a nearly impossible task in the first place.