During the months after President Trump’s election, Israel and many of its supporters in the United States cheered as he promised a new, warmer relationship, such as a more lenient approach to settlements in the West Bank and moving the American embassy from Tel Aviv to Jerusalem.

But as Prime Minister Benjamin Netanyahu of Israel travels to Washington for the leaders’ first official meeting on Wednesday, things have grown cloudier: Sounding like his predecessors, Mr. Trump has said that settlements “don’t help” the peace process, and he has cast doubt on his campaign commitment to move the embassy.

The meaning of Mr. Trump’s semi-pivot is unclear. But even if the American-Israeli relationship dramatically improves, there are deeper trends at work that threaten its unique qualities.

American support for an increasingly right-wing Israeli policy will mean that Israel will have built more settlements; diplomacy aimed at a two-state solution will be stillborn or abandoned; and violence in the West Bank will require Israel to use force to restore order.

Together we have over 50 years of experience working on and watching the American-Israeli relationship, and what concerns us most is the fraying of shared values that set it apart from other bilateral bonds. Without them, interests alone won’t be enough to maintain its special character. If the administration isn’t careful, it will hasten the unraveling.

America’s relationship with Israel has always rested on two pillars: an affinity of values and a shared strategic interest. Those values have strong roots, secured by a well-organized American Jewish community: Israel, despite its occupation of the West Bank, remains the sole robust democracy in the region; Americans feel a bond with the holy land of the Bible; and the United States supported the creation of a Jewish state after the Nazi genocide.

The strategic pillar is much more modest. It was rooted in the Cold War, when Israel was a counterweight to Soviet and Arab nationalist designs in the region and provided the United States with a safe haven for its Mediterranean fleet in return for access to American weapons.

And, truth be told, the two countries are an awkward strategic fit. America is Israel’s ultimate security guarantor, but Israel can’t come close to reciprocating. Israelis have their hands full at home, and the Israeli military would not be welcome in places America might be at war.

In the past, the weakening of the strategic pillar has been made up for by the strength of the values pillar. But Mr. Trump inherits a relationship with Israel at a critical juncture, in which both pillars are weakening at the same time.

Even if Mr. Trump dismantles the Iran nuclear deal, as he vowed to do during the campaign, Israel and the United States will most likely continue to argue about the best way to deal with Tehran. Whatever rhetoric comes out of the White House, Washington and Jerusalem are sitting in very different places with very different perceptions of the threat that Iran will build a nuclear weapon. And Israel has been an afterthought in America’s engagement in Iraq and, now, Syria, where Israel worries more about Iran and Russia than Mr. Trump does.

But the real concern is over values. The Israeli government and the powerful settler movement are poised to exploit the administration’s perceived pro-Netanyahu stance by expanding settlements and neighborhoods in the West Bank and Jerusalem. The Palestinian national movement will no doubt respond with terror and incitement to violence, undermining its own legitimate case. Given the asymmetry of power, Israel’s response will probably be harsher and increasingly seen as anti-democratic, or worse.

Perhaps Mr. Trump will deliver on his promise to broker a solution to the Israeli-Palestinian conflict. But more likely — either through inattention or acquiescence, or the sheer difficulty of diplomacy — the administration will adopt a laissez-faire approach to Israeli actions.

The American-Israeli partnership will not collapse. Congressional politics, a volatile Arab world and sheer inertia will preserve it in some form. 

What will things look like in four to eight years? American support for an increasingly right-wing Israeli policy will mean that Israel will have built more settlements; diplomacy aimed at a two-state solution will be stillborn or abandoned; and violence in the West Bank will require Israel to use force to restore order. Politics in Israel will continue to drift right amid a deepening conviction that it has no Palestinian partner and against the backdrop of an increasingly dangerous region.

If these things come to pass, the erosion of shared values will quicken. The process is already underway because of a number of trends: the drop in religious affiliation in the United States, particularly among Jews; indifference to Israel among many voters, including key Democratic constituencies; the likely leftward turn of the Bernie Sanders generation; and perceptions of an increasingly unpopular alliance between Israel and the Trump administration. Taken together, they point to the very real possibility of growing distance between Washington and Jerusalem.

The American-Israeli partnership will not collapse. Congressional politics, a volatile Arab world and sheer inertia will preserve it in some form. But the relationship would become a pale version of what it once was and what it could be. And that would be a real tragedy for both nations indeed.

The opinions expressed here are solely those of the author.

This article was originally published in the New York Times.