Cruz and Dewhurst have been busy ripping each other's records — Cruz's allies have blasted Dewhurst as a "moderate" in ads while Dewhurst has attacked Cruz for representing a Chinese company that stole a tire design from a Texas company.

The former mayor has spent the campaign contrasting his private-sector record with Dewhurst's and Cruz's time in government, but has not gone harshly negative against either of his opponents. He also said he's unlikely to, going forward.

"We know the message. People don't want the career politician, they don’t want the government attorney. We do want someone who's made tough decisions and has business experience," he said when asked if he'd attack his opponents more harshly.

Leppert just invested $400,000 more of his own money into the race, and his campaign has moved their ad buys around to concentrate more on his home base of Dallas as well as Houston rather than more rural media markets.

He suggested that Mitt Romney should take a stronger line of attack against President Obama, including exploring Obama's connections to his former pastor, the Rev. Jeremiah Wright. A group of GOP strategists had pushed a super-PAC to invest in attack ads on the subject, but the super-PAC's main financier shot the idea down on Thursday after details of the plan were publicly revealed.

"I think it is going to be important for Gov. Romney to address some of these issues that weren't addressed in 2008," he said. "Much like we're trying to do, it is important to draw the contrasts."

Leppert declined to say who he'd back in the runoff if he didn't make it that far. "I'm going to prefer me in the runoff," he said.