Wherefore art thou, Rubio?

Marco Rubio's absence from a conservative rally in Greenville, S.C., Thursday night has sparked another spat with Ted Cruz.

Rubio had been scheduled to address a convention hosted by Conservative Review on the eve of Saturday's GOP presidential primary. The event featured GOP Sen. Cruz of Texas and retired neurosurgeon Ben Carson, as well as several conservative commentators

But the Republican senator from Florida was a no-show.

"It's pretty simple. We ran behind schedule and couldn't make it," Rubio spokesman Alex Conant wrote in an email. "Trey Gowdy & Tim Scott were there to represent Marco, but unfortunately the organizers wouldn't let them speak."

Gowdy, a South Carolina congressman who represents Greenville, and Scott, the state's junior senator, have endorsed Rubio.

Rubio's last-minute cancellation provoked some grumbling among members of the pro-Cruz audience, according to a news account of the event.

Nationally syndicated columnist Michelle Malkin, a senior editor at Conservative Review, tweeted her dismay:

Cruz spokesman Rick Cruz suggested Rubio's absence was no accident.

“This is a final admission that Marco Rubio isn’t even going to try compete for the votes of conservatives in South Carolina or anywhere else. And who can blame him? Rubio isn’t aligned with conservative on a number of issues. Instead Rubio would rather hide behind false attacks, deceptive campaign tactics, and revisionist history than face voters and defend his liberal record on amnesty.”

That wasn't the only event Rubio missed. On Friday, plane trouble forced him to reschedule an event in Pawleys Island, S.C.