Regular readers know I tend to think Bernie Sanders’ first problem in pursuing the party’s nomination is that he’s still not a Democrat. There is a second problem, though. Hillary Clinton isn’t running.

She was his perfect foil. No, Donald Trump can’t compare. His and Sanders’ styles are too similar. Clinton, the liberal establishment realist, was the best antipode to Sanders’ ruffled bombast.

Clinton’s absence explains, to me anyway, why the Working Families Party didn’t stick with Sanders. The minor political party, mostly active on the east coast, endorsed Sanders last time around but Monday sided with Elizabeth Warren. It was explicit about why. It doesn’t think he can knock off Biden.

Mr. Mitchell and other Working Families Party leaders said in interviews that their endorsement came with a message to other progressive organizations. Rather than passively observe the primary, they said, these groups should choose a side and flex their organizing muscle during the early stages to help knock Mr. Biden off his perch.

Oof!

“If our focus is on victory, we can’t be delusional about it,” Mr. Mitchell said. “You don’t defeat the moderate wing of Democrats through thought pieces or pithy tweets, you defeat their politics through organizing.”

Double oof!

Which leads me to a third problem.

Why vote for Sanders when you can vote for Warren?

—JS