First, although Israel is not as dependent on U.S. support as it was in earlier eras, it is still heavily reliant on access to U.S. weaponry, both advanced weapons systems such as F-35 aircraft or Patriot air defense missiles as well as precision-guided bombs and artillery shells. The United States is not the only country that produces advanced weapons, of course, and Israel has sophisticated defense industries of its own, but reequipping its forces in the unlikely event of a U.S. cutoff would be a difficult and costly process. Israeli strategists have long believed it is vital to maintain a qualitative edge over potential opponents, and the loss of U.S. support would jeopardize its ability to do so over the longer term. Add to this the value of U.S. diplomatic protection—whether in the form of U.N. Security Council vetoes or pressure on other states to refrain from criticizing Israel—and it’s clear that the support Israel gets from the United States would be difficult if not impossible to replace. That’s why many observers believe that all Biden needs to do is threaten to reduce U.S. support and Netanyahu will have no choice but to comply.

Second, although weaker clients are hard to pressure when they care more about the issues at stake, the balance of resolve may now be shifting in ways that strengthen the U.S. hand. The United States has been able to get Israel to alter its behavior when its own interests were more heavily engaged, as was often the case during prior Middle East conflicts. President Dwight D. Eisenhower successfully pressured Israel to withdraw from the Sinai after the Second Arab-Israeli War in 1956, and U.S. officials were able to help persuade Israel to accept cease-fire agreements during the 1969-70 War of Attrition and the 1973 Arab-Israeli War. An angry phone call from President Ronald Reagan to Israeli Prime Minister Menachem Begin also ended a massive Israeli bombing campaign on west Beirut during its 1982 invasion of Lebanon. In each of these cases, U.S. leaders acted forcefully and successfully because they believed that broader U.S. interests were at risk.

This situation may be gradually changing as well. Defending a state that is running a system of apartheid is not an easy task, especially when it now faces plausible though unproven accusations that it is conducting a genocide. No amount of full-court hasbara can fully negate the visual images streaming out of Gaza, or the disturbing TikTok and YouTube videos that have been posted by IDF soldiers themselves, making it harder for groups like AIPAC to retain influence. When Sen. Chuck Schumer, long one of Israel’s staunchest defenders, gives a speech on the Senate floor declaring that Netanyahu’s policies are bad for Israel, you know that the political winds are shifting. Attitudes in the American body politic are shifting, too, especially among younger people. Although there are still formidable political obstacles to making U.S. support conditional on Israel’s conduct—especially in an election year—it is not as unthinkable as it was a few years ago.

I conclude that Washington does have lots of potential leverage here, and the barriers to using it are lower than they have been in the past. But because Israel’s current leaders remain highly resolved on this issue, even credible threats to reduce U.S. support might not lead them to alter course significantly. Nor is it clear if Biden or his advisors can make the mental adjustments necessary to move from their current failed approach to something more effective. Instead of focusing on whether pressure on Israel would work, the real question to ask is simply whether it is in America’s strategic or moral interest to be actively complicit in a vast and worsening humanitarian tragedy. Even if the United States cannot stop it, it doesn’t have to help make it worse.