Since when is Marco Rubio the mean one? At last night's debate he had a few moments of real fire, attacking Donald Trump faster than the walking hairpiece could respond. And he's at it again today, accusing Trump of, among other things, wetting his pants.

As Dave Holmes commented on Twitter last night, "If this were some other country's presidential debate, you would make a point of never visiting that country."

Rubio went after Trump on his vague health care plan (Trump kept saying they'd end health insurance monopolies but didn't have any other specifics), for his phony Trump University (which bilked people for thousands of dollars in exchange for a few real estate tips), for his hiring of illegal labor, and for being an heir who never had to work thanks to his dad's fortune.

Rubio called him a con artist, and Trump in turn called Rubio a "choke artist," referring to that previous debate when Rubio seemed to start glitching out.

Will any of that make a difference with voters? Who knows — the people supporting Trump aren't doing so because they are rational, so maybe an appeal to angry emotions will get through to them. Currently Trump's projected to win in almost every upcoming Republican primary.

So today, Rubio kept up the assault.

He told a crowd that during breaks, Trump "asked for a full length mirror, I don’t know why because the podium goes up to here. I don’t know why. Maybe to make sure his pants weren’t wet."

I'm sure that line killed in whatever 3rd-grade class he was addressing at the time.

Donald's definitely mad about last night, and has been firing off a string of typo-laden tweets at Rubio. He attacked Rubio's "honer," called him a "chocker," and said he's "leightweight."

Rubio made fun of him for the misspellings, too — but he messed up the punchline: "He spelled choker, C-H-O-K-E-R."

Oh well, good try, Marco.

For his part, Trump's still providing plenty of fodder for attacks: Republicans terrified that he'll be the nominee are laying into him now for not releasing his tax returns. Last night he said he couldn't because he's being audited, and today experts are all shrugging because of course you're free to release your tax returns even when you're being audited.

So what could be in those returns?

I think the most likely embarrassment might have to do with donations. Trump might turn out to be lousy at charitable giving; or he might turn out to have given money to causes that are not particularly Republican.

Or maybe the tax returns reveal that he's a crying little pants-wetter.