The Biden administration’s betrayal of Israel in respect of the war against Hamas marks a nadir in America’s relations with the Jewish state. There have been some difficult times, no doubt. Think of the Suez Crisis in 1956, say, when we essentially forced Israel’s retreat. Or Israel’s attack on Beirut, when Reagan vented against Prime Minister Begin. Or, say, the boycott by leading Democrats of Prime Minister Netanyahu’s speech in 2015 to a joint session of Congress.

This has been well reported by our Benny Avni, most recently yesterday afternoon in his story suggesting that President Biden is weighing halting war materiel if Israel does not agree to Washington’s view of how the battle against Hamas should proceed. It is a heartbreaking moment for those of us who have been invested in the Zionist cause. The Wall Street Journal, in an editorial Monday, goes so far as to suggest Democrats have turned against Israel.

Mr. Biden is at pains to try to convince his countrymen that this is about Prime Minister Netanyahu. This is the lie that Senator Schumer tried, in his 6,000-word speech the other day to the Senate, to palm off on his noble comrades. Mr. Biden loathes the Israeli leader and is furious that Israel voters keep electing him. Mr. Schumer is oblivious to the fact that an all-party war cabinet has been working together in the Battle of Gaza.

It is breathtaking how quickly Mr. Biden turned on Israel. After October 7, after all, he appeared to stand by our Mideast ally. His defense secretary, Lloyd Austin, on his own visit to Israel, said he’d worked with the Israel Defense Forces before and assured Americans that the IDF knows what they are doing. Mr. Biden himself became the first American president to fly over at time of war. And to sit with the Israeli high command in its war room.

Yet it took only some street protests at downtown New York, in front of the White House, and, crucially, at Dearborn, Michigan, to make Mr. Biden fret that his second term depends on a few pro-Hamas, leftist know-it-alls lurking within his own party. For Mr. Biden, it seems, politics does not stop at the water’s edge, as  Senator Vandenberg told Truman it did when the Cold War was in its early years. The doctrine helped us win the Cold War.

Yet, is it really a smart political move for Mr. Biden to base America’s foreign policy on the “uncommitted” leftist fringe in Michigan and Arizona. There is, after all, a healthy pro-Israel majority in our country. Why wouldn’t Mr. Biden focus on winning over the uncommitted voters, rather than on alienating our bipartisan backers of a strong alliance between America and Israel? Why not try to sway the “from the river to the sea” crowd?

Instead, our Mr. Avni reports, a group of seven Democrats, led by Senators Van Hollen, Merkley, and Sanders, alleges that Israel is violating the Foreign Assistance Act of 1961. They urged Mr. Biden to limit offensive arms to the IDF. It may be that in the end Mr. Biden won’t take that kind of drastic — and uncalled-for — step. That the Democrats are even airing the possibility, though, is dangerous enough — an invitation for Israel’s enemies to attack

Late Monday, the White House did announce that it asked Israeli war planners to come to Washington, so American counterparts could lecture them about the pitfalls of fighting at Rafah. The reports at Jerusalem are that an Israeli team will make the trip. America, too, has some brilliant officers. The idea, though, that America might cut off the ammo if the Israelis don’t fight the war their way strikes us as shocking.

For four generations America and Israel have maintained one of the great values-based alliances in modern history. It has brought great benefits to both sides. The danger is that Mr. Biden’s instinct for appeasement will lead him to make the same kind of mistake with Israel that he did in helping force an abandonment of Vietnam, Iraq, and Afghanistan. It would be a tragedy for the Democratic Party that seems to be bent on marching off in that direction.