BURBANK, California (Reuters) - Republican presidential candidate Mitt Romney had this assignment for Rick Santorum on Tuesday to make light of his chief rival's frequent tussles with the news media: "Press secretary."
Romney, who sometimes struggles to connect with everyday voters, appeared on NBC's "The Tonight Show with Jay Leno" for an interview that was at times serious and at times humorous.
He was about 30 seconds into the appearance when he found himself talking about the dull process of collecting delegates for the Republican presidential nomination, not the type of material normally covered by late-night television comics.
"Well, they allocate the delegates on a proportional basis this time, so we knew it was going to take awhile," Romney said in the taped appearance that media were allowed to watch.
Then the strait-laced former Massachusetts governor was quickly sidetracked into commenting on Santorum's recent vow to crack down on pornography if he were to be elected president.
"Did you ever think we'd be talking about porn, with all the other things in this election?" Leno asked.
"I didn't know we were talking about porn," Romney said to laughter from the audience.
Romney was revealing when asked to talk about several Republican heavyweights who might be vice presidential material should Romney go on to win the nomination to face Democratic President Barack Obama in the November 6 election.
"I'll tell you what," said Romney. "I can do you a favor with this. I'll choose David Letterman. We can help us both out."
Letterman of CBS' "Late Show" is Leno's chief rival for the late-night comedy audience.
Asked for one-word descriptions of big-name Republicans: Romney called New Jersey's super-sized governor, Chris Christie, "indomitable."
"He's a man of strong will. Great strength. Indomitable," said Romney.
Leno's reply: "Man of girth."
TRUMP IS 'HUGE'
Of Florida Senator Marco Rubio, Romney said he represents "the American dream." South Carolina Governor Nikki Haley is "energetic," he said, and real estate mogul Donald Trump is "huge."
Asked his one-word description of Santorum, Romney replied, "Um, press secretary," a reaction to Santorum's verbal jousting with a New York Times reporter on Sunday.
In fact, Romney did not rule out picking Santorum for the vice presidential slot and said the former Pennsylvania senator's scrap with the reporter was understandable given the stresses of the campaign. He called him a "good guy" who has run a good campaign.
"I'm happy with him saying he'd like to be part of an administration with me, nothing wrong with that, if he's the VP that's better. I'd rather be the president, let him be the vice president," said Romney.
On the serious side, Romney insisted that if elected, he would repeal the controversial healthcare overhaul engineered by Obama but suggested he would keep a popular provision that forbids health insurance companies from denying coverage to people with pre-existing medical conditions.
"People with pre-existing conditions, as long as they have been insured before, they are going to be able to continue to have insurance," he said.
Romney took a dim view of Obama's open-mic blunder with Russian President Dmitry Medvedev in South Korea in which Obama seemed to promise a more flexible U.S. position on missile defense with Russia should he win re-election.
He defended his description of Russia as the top U.S. geopolitical foe after drawing criticism from Democrats for the assertion.
Russia's leaders, he said, support countries like Iran, Syria, Venezuela and Cuba, which all have tense relations with Washington.
"They basically stand up for the world's worst actors, and when America tries to put pressure on those actors with sanctions or other U.N. actions, Russia always stands up for what I would consider to be the world's worst leaders," he said.
(Editing by Mohammad Zargham)