Some of them have better lines than others, and some joke more or hector less. But to flip from Stephen Colbert’s winsome liberalism to Seth Meyers’s class-clown liberalism to Bee’s bluestocking feminism to John Oliver’s and Trevor Noah’s lectures on American benightedness is to enter an echo chamber from which the imagination struggles to escape.

It isn’t just late-night TV. Cultural arenas and institutions that were always liberal are being prodded or dragged further to the left. Awards shows are being pushed to shed their genteel limousine liberalism and embrace the race-gender-sexual identity agenda in full. Colleges and universities are increasingly acting as indoctrinators for that same agenda, shifting their already-lefty consensus under activist pressure.

Meanwhile, institutions that were seen as outside or sideways to political debate have been enlisted in the culture war. The tabloid industry gave us the apotheosis of Caitlyn Jenner, and ESPN gave her its Arthur Ashe Award. The N.B.A., N.C.A.A. and the A.C.C. — nobody’s idea of progressive forces, usually — are acting as enforcers on behalf of gay and transgender rights. Jock culture remains relatively reactionary, but even the N.F.L. is having its Black Lives Matters moment, thanks to Colin Kaepernick.

For the left, these are clear signs of cultural gains, cultural victory. But the scale and swiftness of those victories have created two distinctive political problems for the Democratic Party.