The Democratic Party is on the cusp of abandoning the state of Israel. That’s a shame, though less for Israel than it is for the Democrats.

The Democrats’ historic support for the Jewish state has always been what’s best about the party. The understanding not only that Jews are entitled to a state, but also that a liberal democracy is entitled to defend itself—robustly and sometimes pre-emptively—against illiberal enemies, is why the party of Harry Truman, Scoop Jackson and Daniel Patrick Moynihan commands historic respect....