Schieffer: No clear winner of 20th GOP debate

The last scheduled debate of the Republican presidential primary race failed to produce a clear winner before back-to-back weeks of closely watched contests, Bob Schieffer said on "CBS This Morning" Thursday.

Next week, voters go to the polls in Arizona and Michigan, the home state of former Massachusetts Gov. Mitt Romney, with former Pennsylvania Sen. Rick Santorum putting up a strong fight against Romney in both contests. But neither delivered a knockout punch in Wednesday night's debate in Mesa, Ariz., Schieffer told Erica Hill and Charlie Rose.

"I don't think this was a debate that changed very much, quite frankly," said Schieffer. "It was obviously Santorum versus Romney, but, you know, I suppose the people that like Rick Santorum going in thought he did well and those that like Mitt Romney going in thought he did well, but I don't think there was any, any great moment."

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Robert Gibbs, a senior adviser to President Obama's re-election campaign, told Schieffer that the debates have been generally helpful to the president.

"If you're an independent or undecided voter and you turned in, tuned in to last night's debate, I don't doubt at all that you have been turned off by the type of nasty, negative, carpetbombing distortions on each other and on the president's record," said Gibbs. "I don't sense that they're talking about the issues that people care most about. That's what the president's spending, uh, his time talking about, Bob."

Gibbs also played off a comment made earlier by Schieffer, who said the last scheduled primary debate felt like the last episode of the hit PBS series "Downton Abbey" with fans left wanting more.

"I don't think there's any doubt," said Gibbs, "that we got more out of 'Downton Abbey' than we have out of these 20 debates."

Above, watch full debate analysis from Bob Schieffer and Robert Gibbs