Mitt Romney will not be attending the upcoming Republican presidential debate moderated by Donald Trump, citing scheduling conflicts.
"No, I'm not participating in that," Romney said Tuesday during an interview with Fox News. "The rest of the month is going to be spent campaigning … we'll be hitting the trail."
Romney said he called Trump earlier Tuesday to tell him that he would be unable to participate.
Jon Huntsman and Rep. Ron Paul (Texas) have already said that they would be skipping the event, arguing that Trump's resume as a reality TV show host delegitimized the presidential process. Trump blasted back at both men during a series of radio and television appearances this week.
"I'm not saying I'll be better, I'm saying I'll be different," Trump said Tuesday on the Laura Ingraham Show about moderating the debate. "Who knows better? I've never done it before, maybe that will be a good thing."
He went on to describe Huntsman's criticism as a "disgusting statement" and dismiss Karl Rove — a former adviser to President George W. Bush, who made a similar critique — as a "political hack."
But Romney avoided criticizing Trump directly in declining to appear at the debate.
"I think there are several other debate requests we've had for December and January, we just can't do them all," Romney said.
Newt Gingrich has committed to appear at the debate, while Rep. Michele Bachmann (Minn.) has wavered on her participation.
Romney also said Tuesday that he would support the extension of the payroll tax cut currently being championed by President Obama and congressional Democrats, although he argued that, by itself, it would be ineffective in improving the economy.
"I would extend it because this is not the right time to raise taxes, but I would not pay for it by increasing taxes on other people," Romney said.
"It's not going to reignite the economy, it's not going to put Americans back to work."
Asked about a recent slip in the polls — conservative support seems to have coalesced around Gingrich after businessman Herman Cain suspended his campaign following allegations of sexual impropriety — Romney acknowledged that his campaign would be stepping up efforts to reach voters, including an increasing number of interviews on Fox News. He will appear on the channel's Sunday talk show, his first such appearance this news cycle.
"We're going to make sure our differences will be well aired," Romney said, referring to his battle with Gingrich.
But Romney eluded a question about what narrative his campaign would seek in fighting against Gingrich.
"His role as Speaker in the House will be measured carefully," Romney said. "I don't know what that will show in regards to him."