The inertia of progressives—young or old—isn’t hard to explain. Few are enthusiastic about the Affordable Care Act. The deals needed to pass it, the lack of a public option, and the High Court’s decision to let individual states refuse to expand Medicaid all dilute the moral vision of universal health care the left promoted for nearly a century. And Barack Obama has done a poor job explaining why most Americans will benefit from the law. My wife has an “I Love Obamacare” bumper sticker on her car. Even where we live, in a super-liberal Maryland suburb just a mile from the DC line, I rarely see another one.

Despite what the polls say, Americans on the left also harbor a deep cynicism toward the federal state. While their mistrust is directed at campaigns funded by the rich and the military and security establishment rather than entitlements, it still leads them to balk at efforts to champion a government and an administration that fail to live up to their liberal promises.

Ironically, the only time in recent years that progressives did manage to organize something resembling a mass movement was when they helped elect Barack Obama in 2008. Not since Franklin D. Roosevelt’s landslide re-election in 1936 had left and liberal activists united, with enthusiasm, to work in a victorious presidential campaign. But a run for the White House is not the same as a popular insurgency, and a president cannot be the leader of a movement.