Joseph R. Biden Jr. made some serious news Sunday night.

He did so with a clear, concise and deftly inserted pledge: He said he would name a woman to run with him if he wins the Democratic Party’s presidential nomination.

There. It’s done. The former vice president effectively eliminated by roughly half the number of candidates he might consider running with him.

That doesn’t mean he’s got a short list. Oh, no! It means only that he has made what sounded to me like an ironclad pledge to select a woman as his running mate. He also seemed to suggest that a woman who debated him on the 2020 primary stage would have an advantage in the selection process.

Whoa! Not so fast, Mr. Vice President.

The nation is chock full of women who could serve today as president. They are governors, former governors, former senators, former House members, in addition to current officeholders. The field is full. I do not want him to limit his choices, even though he’s done so with the remarkable pledge he made on that debate stage with Bernie Sanders.

So … Joe Biden has just made a big splash.

Wow!