The latest failure of Senate Republicans to repeal Obamacare after repeatedly promising to do exactly that offers a basic political lesson for both sides: benefit programs create their own constituencies.

This should be obvious, but many Democrats seem to be just starting to realize it, and only after a long struggle. It can be seen in the number of Democrats suddenly lining up behind Bernie Sanders’s Medicare-for-All bill: Cory Booker, Kirsten Gillibrand, Kamala Harris, Elizabeth Warren — all top contenders for the party’s nomination in 2020, along with Sanders, of course. For some, like Warren, this has been an evolving stance over several years; for others, like Al Franken, the change of heart seems to have come from spending a couple hours on Twitter.

Hillary Clinton, too, gets it, belatedly. In her post-election postmortem What Happened, she writes: