Mike Bloomberg has run in four contested primaries or elections for mayor of New York City; each time, he debated his opponent twice. We listened to the first one, which was on radio, and watched seven on TV.

Now, he’s eager to debate his rivals for the Democratic presidential nomination.

But Mr. Bloomberg wasn’t on the stage last Tuesday night in Des Moines, just 20 days before the Iowa caucuses. He was absent because the Democratic National Committee, which should be trying to find the strongest candidate to beat Donald Trump in November, has really dumb debate qualification standards.

The DNC says to make it to the big show, candidates must register a minimum level of support in national and/​or early state polls, which makes sense, and collect contributions from at least 225,000 different people, which doesn’t.

The idea is to encourage candidates to develop a broad-based small-donor fundraising operation. But for a wealthy candidate committed to self-funding his campaign, that’s irrelevant.

To see the fallacy of it all, compare Mr. Bloomberg, who didn’t make the cut, with fellow self-funding billionaire Tom Steyer, who did.

Both get over the bar in polling. But only Mr. Steyer spent millions on social media ads to cadge contributions of a buck or two, just to satisfy the DNC’s silly criteria.

Mr. Bloomberg could ape Mr. Steyer’s strategy tenfold if he wanted to. He doesn’t, and we say, good for him.

The DNC is averse to changing the rules in the middle so late in the game, and for a white billionaire at that. We get the political predicament, but the party of gun safety is shooting itself in the foot.

First Published: January 20, 2020, 9:15 a.m.