President Trump and Israeli Prime Minister Benjamin Netanyahu shake hands after Trump’s address at the Israel Museum in Jerusalem last May. (Ronen Zvulun/Reuters)

Aaron David Miller, a former State Department Middle East analyst and adviser in Republican and Democratic administrations, is a vice president and director of the Middle East program at the Woodrow Wilson Center. Steven Simon, a professor at Amherst College, served as senior director for the Middle East and North Africa on the National Security Council from 2011 to 2012. He is also the author of the forthcoming book “The Long Goodbye: The US and Middle East from the Islamic Revolution to the Arab Spring.”

For decades, the United States’ relationship with Israel has been sustained by a bipartisan consensus in Washington. Both Republicans and Democrats have had their own close relations with the Jewish state, and both have agreed that supporting it has been a vital national interest.

Yet today we see that U.S. support for Israel is becoming an increasingly partisan issue, willfully exploited by politicians both here and in Jerusalem. This growing trend is undermining the consensus that has long made the U.S.-Israeli bond so special. If this bipartisanship is compromised, it’s only a matter of time until the special relationship will be as well.

The current administration is now consolidating a link between Israel and the Republican Party that its predecessors never pursued quite so single-mindedly.

The numbers are in: According to a recent Gallup poll, there is now a historically unprecedented 38-point gap between Republican and Democratic sympathy for Israel versus the Palestinians. And this gap could widen over time as the Hispanic vote grows, younger evangelicals prioritize other concerns and the Democratic party tilts to the left.

Together we have a combined total of 50 years of experience involving the U.S.-Israel partnership — and never have we felt more concerned about its prospects than we do today.

Overall, Americans continue to favor Israel. But there is a growing divide between Republicans and Democrats that is fundamentally unhealthy for U.S.-Israeli ties. Bipartisan support for Israel reflected the postwar liberal moment, when Americans saw the best of themselves in looking at Israel: patriotic but pluralistic, fierce defenders of sovereignty but attentive to civil liberties and human dignity, respectful of tradition but innovative and resilient. A country that fought and won defensive wars, fair and square. A shared view of Israel made us prouder of ourselves and ready to hold ourselves to a higher standard. Support for Israel, in short, was American. Democratic supporters of Israel today long for a return to this moment.

Many Republicans, especially those who have repudiated the legacy of the more traditional internationalist party of the postwar period, now tend to see Israel in terms that are more in tune with their own self-conception: wary of outsiders, belief in efficacy of unilateral action and self-reliance, subordination of humanitarian interest to strategic concerns, a majoritarian impulse that equates tribe and nation, and a preference for hard power in managing strategic challenges.

None of these images of Israel has ever been entirely accurate, nor are these characteristics consistently good or bad in all circumstances. But the shattering of our shared image of Israel and its transformation into a political football — a shift that a changing Israel has encouraged — will ultimately diminish ourselves. Why? Because it deprives us of a communal symbol and shared value as our social cohesion is becoming increasingly frayed.

It is also dangerous. Alliances are most vulnerable when they are perceived to be weakening. And a United States divided regarding Israel might forgo intervention on its behalf in a crisis, in a way that could create doubts about American reliability while forsaking a solemn commitment to a people that had passed through the gas chambers and crematoria.

Israel is especially significant to American Jews, a diverse religious and ethnic community. A partisan approach to Israel essentially cuts off many American Jews from a focus of their emotional and historical roots. It devalues some American Jews while privileging others. This is deeply un-American.

Israel is changing, too. It is more religious, more right-leaning and, in some respects, less Westernized than in the past. It is also more inclined to devalue the civil liberties of Israeli Arabs and feels safer controlling the West Bank than not. And it sees increasing promise in ties to non-Western countries than to Europe and a United States that urges territorial compromise and supports a Palestinian state.

There are, to be sure, offsetting factors that may slow the bipartisan unraveling. Israel remains the only democratic polity in an undemocratic region and the only nation with whom the United States shares both values and interests. And the anti-Americanism and bad behavior of any number of regional actors — Iran, al-Qaeda, Syrian President Bashar al-Assad, Hamas and Hezbollah — will ensure that Washington will look to Israel as a force for stability and good in the Middle East.

Still, countries develop along their own unique trajectories. A century of protracted conflict, the shadow of the Holocaust, the pull of religion and nationalism, the power of demographics and an unresolved Palestinian issue have shaped the evolution of Israel’s state and society and are pulling Israel in one direction. A set of different forces has produced a deeply divided America and set it moving in another uncertain direction.

None of this is set in stone or hostage to inexorable forces. Pragmatic leaders with courage and vision can bend the future for good and positive change. We hope that for the sake of both countries, such leaders will emerge. It would be a tragedy for the United States and Israel and for the future of a troubled Middle East if they didn’t.