The first Democratic presidential debate featured random monologues in Spanish, a testy debate between Tulsi Gabbard and Tim Ryan, and almost no mention of the candidate polling better than everyone else in the Democratic field: Joe Biden.

The challengers were reticent to mention the front-runner (why didn't the moderators bring him up?) instead choosing to make an affirmative case for their own agenda and Trump #resistance bona fides. But Biden is averaging 32% in the polls, twice that of Sen. Bernie Sanders, I-Vt., who is in second place.

Candidates can’t run away from a lead that big.

If they want to catch up to Biden, challengers flailing at 1% have to make the case against him and the “return to normalcy” his campaign symbolizes for many. There’s ample ammo to do that — whether it’s Biden’s support for a disastrous 1994 crime bill, praise for segregationist senators, support for the failed Iraq War, or creepy behavior toward women.

But Democratic challengers will have to deal with Biden’s candidacy eventually. Until they do, we’re left wondering: What are they so scared of?