Rubio — correctly — called Trump "orange" and a "con man." He also, perhaps spuriously, laughed at Trump's allegedly tiny baby hands and suggested that his fingers weren't the only undersize part of his anatomy. The moment was a hilarious commentary on the carnival sideshow the GOP race had become. But it wasn't a shining moment in Rubio's meteoric political career.
This past weekend, Rubio revealed that he had called the Donald in private and apologized for the crack.
"I actually told Donald, I apologized to him for that," Rubio told CNN's Jake Tapper. "I said, 'I'm sorry that I said that. It's not who I am. I shouldn't have done it.'"
On the one hand, Rubio's revelation taps into his uncomfortable move into the role of Trump apologist now that the real-estate magnate has wrapped up the Republican nomination. Rubio has already said he'll vote for the guy he very recently called "dangerous" and a "strong man" who shouldn't have nuclear access codes.
But Rubio, to his credit, didn't walk back on the underlying reason behind his tiny-penis jokes. Trump had figured out how to hack the cable news cycle: Lob absurd insults and accusations, dominate free media
So Rubio gave it a shot. At a Virginia campaign stop, he went full late-night comedy routine on Trump:
Rubio told Tapper the moment wasn't planned; it was the result of seething frustration at how Trump's game plan was working.
"There wasn't any meeting or anyone on my staff. It was just enough is enough," Rubio told Trapper of how the joke came about. "This guy is out there every day mocking people for their appearance, for this and that. Eventually, someone has to step forward and say, 'Enough is enough,' and put an end to this."
Yet when Rubio tried the same medicine, he quickly found it didn't work. Trump pointing and laughing at a disabled reporter is Trump being Trump, Rubio found, while Marco making similar jokes at the Donald's expense was a shock.
"This guy is out there every day, mocking people, saying horrible things about people, but if you respond to him, somehow you're hitting below the belt? That was my sense of it at the time," Rubio says.
The reason: It didn't make his carefully stage-managed profile as a slick "presidential" character.
"I didn't like what it reflected on me. It embarrassed my family. It's not who I am," Rubio says.
That's not to say it didn't work, though. Tapper could only laugh uncomfortably when Rubio pointed out, "After I did that for four days, all of my speeches were covered live on cable. They all broke in in case I said something else."
Rubio's interview points to a problem that Hillary Clinton is already having serious trouble navigating. Responding to Trump insult-for-insult doesn't work, but candidates have to do something to break his stranglehold on the news cycle.