Two GOP frontrunners are headed for a face-off in Saturday night's ABC News debate in Iowa. But for Democrats, the focus remains on one man alone: Mitt Romney.

In a pre-debate memo to reporters, Democratic National Committee vice chairman and Minneapolis Mayor R.T. Rybak doubles down on the party's critique of the former Massachusetts governor, while only briefly mentioning former House Speaker Newt Gingrich - despite his rise in the polls.

Rybak says Gingrich's challenge of Romney in Iowa, evident in the most recent ABC News/Washington Post survey of likely caucus goers, has forced the once presumptive GOP nominee to "abandon his general election playbook in favor of a sharp turn to the right."

"Unable to convince voters he's still the cool-headed, presumed Republican nominee to face off against President Obama in the general election," Rybak writes, "Mitt Romney has thrown out his general election strategy, now telling Republican primary voters whatever they want to hear and launching broadside attacks against Newt Gingrich."

Rybak, who is in Iowa to offer a Democratic rebuttal to the debate, alluded to Romney's pattern of shifting positions on some hot button issues - including the payroll tax cut extension - and his campaign's all-out offensive against Gingrich over the past two days.

"It's shameless political pandering - and Romney's extreme positions won't sit well with most voters in the general election next year," Rybak said.