What does Mike Bloomberg think he's doing?

3. It’s a public-relations disaster for a Democratic Party trying to keep leftists and moderates in harmony.

The Democratic National Committee has insisted that to qualify for its official debates, candidates must surpass a donor threshold. Since Bloomberg isn’t accepting donations, those rules have so far barred him from the debate stage.

But on Friday, after Bloomberg moved into fourth place in national polling averages, the DNC junked its donor-threshold rule for the February 19 debate in Nevada. This opens the door for Bloomberg’s participation—and to complaints of preferential treatment for a Johnny-come-lately billionaire who doesn’t deserve it.

Beyond process issues, the debate itself could be—to use a technical term—super awkward: The billionaire mayor will have used his fortune to gain entry into a debate about whether such extreme wealth should be taxed into extinction. Perhaps a showdown between Bloomberg and Sanders will produce a valuable discussion on the merits of lucrative entrepreneurship versus radical redistribution. Or it could widen the rift between older, cautious, anti-socialist moderates and young, fierce, anti-plutocratic revolutionaries.