Manchester, New Hampshire (CNN) - Appearing poised for another feisty debate performance, former Sen. Rick Santorum is focusing his conservative barbs on newly-ascendant candidate Herman Cain.
Santorum's criticism at a campaign stop of the former Godfather's Pizza CEO is one sign that Cain will experience the traditional role of a front-runner in the debate Tuesday night: that of punching bag.
Cain has surged in popularity in recent weeks, in part due to his signature plan to do away with almost all current taxes and replace them with a flat 9% tax on income, a 9% corporate tax and a 9% national sales tax. The policy has become a catch phrase on the trail and is an example of Cain's straight-talking style that has resonated with conservatives.
Speaking to reporters outside a diner in Manchester Tuesday morning, Santorum immediately launched into a critique of Cain's 9-9-9 policy.
Calling himself the true conservative in the race, Santorum positioned himself to the right of Cain on taxes.
"Zero-zero-zero is better than 9-9-9," he said Tuesday, a reference to his plan to eliminate the corporate tax rate for manufacturers and dismantle Obama-era regulations. The mantra echoes criticism Santorum made about Cain's plan at the Values Voter Summit on Friday.
Santorum pointed out Tuesday the state of New Hampshire does not impose a sales tax and likened Cain's plan to a tax increase.
"Herman Cain now wants to impose a 9% sales tax, not just on New Hampshire but on every state in the country," Santorum said. "I don't think giving the federal government a new tax is tax reform. I think it's going to be punitive to a lot of people."
The two-term Pennsylvania senator barely registers in national polls but has stood out in recent GOP debates by landing blows against his competitors from the right.
Cain's second-place standing in several national polls earned him a central spot at the Tuesday night at Dartmouth College. Cain will be seated next to front-runner and former Massachusetts Gov. Mitt Romney, with Texas Gov. Rick Perry in the next seat over from Cain. In recent debates Perry had shared center stage with Romney.