Unlike the NRA, AIPAC must do business with whoever runs Congress and the White House, policy disagreements notwithstanding. Thus, when President Obama in 2011 invited the NRA to the White House to discuss gun safety, LaPierre responded: “Why should I or the NRA go sit down with a group of people that have spent a lifetime trying to destroy the Second Amendment?” But that December, AIPAC CEO Howard Kohr attended the White House Hanukkah party.

But AIPAC doesn’t only fear polarization because it could undermine its influence. It also fears polarization because it could split the organization in two. Unlike the NRA, which according to a 2017 Pew Research Center poll boasts a membership that is more than three-quarters Republican, AIPAC’s members are likely split fairly evenly between the two parties. When Vice President Mike Pence praised Trump on Monday night, around half of the AIPAC attendees stood up to applaud.

AIPAC’s problem is that its bipartisanship is becoming harder to maintain. Democrats may constitute roughly half of AIPAC’s members, but their share could plummet in the years to come. The reason is simple. Many older American Jews see Israel through a different lens than other issues. Their broader liberalism inclines them to vote Democratic. But their anxiety about Jewish safety and commitment to the Zionist project incline them to join AIPAC.

AIPAC’s problem is that younger American Jews are less likely to bifurcate their views in this way. They are less likely to have personally experienced anti-Semitism. They are less likely to know relatives who survived the Holocaust. And they are less likely to have witnessed events like the 1967 and 1973 wars, when Israel’s existence appeared to be in peril. To the contrary, they have come of age seeing both American Jews, and the Jewish state, as privileged and powerful.

Thus, they are more likely to inherit their parents’ progressivism than their parents’ Zionism. The same concern for human rights and equality that informs their general political outlook makes them unsympathetic to Israel’s policy of holding millions of Palestinians under military occupation, without basic rights, in the West Bank. Which puts them at odds with AIPAC. They are also generally more assimilated than their parents, which means that—irrespective of their politics—they care about Israel less. Which means they’re less likely to join AIPAC.

It’s not that AIPAC doesn’t attract young people. It does. But those young people are disproportionately Orthodox. Orthodox Jews are rising as a share of the American Jewish population. And younger modern Orthodox Jews—many of whom attend intensely Zionist yeshiva day schools and spend a year studying in Israel between high school and college—generally feel a stronger connection to Israel than their non-Orthodox counterparts.