Mass movements stoke the fires of popular discontent, but only the state can pass laws and overhaul key institutions.

ainstream Democrats and leftists are at each other’s throats again. Senator John Fetterman denounces progressives who condemn the war in Gaza and oppose strict limits on undocumented migration. Anger at President Biden’s support for Israel spawns hashtags like #GenocideJoe and pledges to vote for Jill Stein, Cornel West—or refusals to cast a ballot at all. The broad center-left coalition that united to resist Trump as soon as he moved into the White House—and then humbled the GOP at the polls in 2018 and 2020—is coming apart. Knitting it back together before November will be difficult—but vital.

Neither side seems to have learned a basic truth from the history of American politics: Democrats and leftists, liberal politicians and radical insurgents have always depended on each other to accomplish essential, if not sufficient, ends.

But they have often been able to work together for common purposes and to oppose a common enemy. In 2024, failure to find such a modus vivendi would allow a vicious authoritarian and his reactionary party to control the entire federal government again. Victory for Trump and his partisan faithful would set back the chance to build a kinder, more egalitarian, and peaceful society for years to come.

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