This was supposed to be the presidential primary race in which the progressive wing of the Democratic Party put it all together. The left was coming for power, not only moral victories. One popular podcast promised that the party’s moderates would soon “bend the knee,” as working Americans flocked to a left-wing presidential agenda.

But after a disastrous month of electoral drubbings that continued with Tuesday’s primaries in Arizona, Florida and Illinois, it has become clear that the presidential promises of political revolution and big structural change will once again have to wait.

Former Vice President Joseph R. Biden Jr. is not just beating liberal rivals, all but vanquishing Senator Bernie Sanders of Vermont and outlasting Senator Elizabeth Warren of Massachusetts. His candidacy has poked significant holes in the strategy of their wing of political thought.

Their big investments in organizing could not overcome his name recognition. They could not reshape the primary electorate, while Mr. Biden has surged among more moderate voters in Democratic suburbs. They could not cut into his advantage with black voters. And they could not overcome his electability argument — that he is the best candidate to defeat President Trump — as evidenced by the fact that Mr. Biden bested Mr. Sanders with many liberal voters in Florida on Tuesday.