Marco Rubio and Patrick Murphy. Photo: Joe Burbank/TNS via Getty Images

One of the weirdest political decisions of this election, at least among decisions in the non-Trump category, is the Democratic Party’s lack of commitment to unseating Marco Rubio. The Democratic Senatorial Campaign Committee is pulling its remaining ads on behalf of its Senate candidate, Patrick Murphy, despite public polls showing Rubio leading him by as few as two points. It’s likely private polls show Rubio leading by more, but polls can turn out wrong. In a race where the presidential candidate is in danger of collapse, small leads by down-ballot candidates can disappear quickly. The Miami Herald, which endorsed Rubio in previous elections, has endorsed Murphy this time.

The official reason for the choice is that Florida is an expensive state for advertisements, and Missouri and North Carolina offer pickup opportunities for much less investment. But this misses an important additional reason Florida matters: Rubio is the best hope for the future of the Republican Party’s donor class. Rubio is almost surely going to run for president in 2020, and he gives his party the cheapest possible concessions to the center — an appeal to moderates with affective moderation and well-honed performative qualities, rather than concessions on policy. Rubio memorably expressed his disgust with Trump in a way that made the news media and anti-Trump Republicans alike swoon, but without committing himself to any course of action that might alienate Trump’s base:

Yes, Rubio was steamrolled in the primaries. But not every candidate who loses is a bad politician. If Rubio holds his Senate seat by a few points or less, and then wins his party’s nomination in four years, Democrats will be kicking themselves they didn’t pull out every stop to end his political career, in the short term, when they had the chance.