But the bad news for Israel is that Mrs. Clinton alone cannot resist what seems to be a steady drift in her party. The more Democratic voters identify as liberal — and the more liberal they are — the less they support Israel. Political reality will ultimately catch up with Mrs. Clinton and other moderate Democrats. In Congress, a sidling away from Israel among Democrats may already be underway. Once, Democratic legislators had to worry about appearing unsupportive of Israel; today some of them — especially those who need to be re-elected by liberal voters — seem to have the opposite concern: They do not want to be seen as too supportive.

Some high-ranking Israeli politicians tell me that they believe changes in Israel’s policy could quickly end Americans’ growing discontent with their country. Improved relations with the American Democrats, the anti-Netanyahu figures say, is one of the many rewards Israel will receive when it comes to its senses. For this to happen, they say, the government must demonstrate that it supports a two-state solution. But that is not an easy move for the current hard-line governing coalition.

Soberer Israelis — and American conservatives — ridicule such suggestions because they believe the liberal constituency of the Democratic Party is moving leftward, toward a domain where condemnation of Israel is fashionable, and there is little Israel can do to reverse what is an American trend.