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As a former senator from Pennsylvania, Rick Santorum has claimed a prospective advantage come November, if he carries the party's colors: That his blue-collar background and manufacturing-driven economic plan position him to defeat President Obama in "rust-belt" states such as Pennsylvania, Ohio and Michigan, states that the GOP ceded in 2008.

"I'm the best person, from a state which is a key swing state, from a region of the country which is going to decide this election, right across the rust-belt of America," Santorum said onstage in CNN's Mesa, Ariz., debate in February.

It's an appealing argument, particularly given Democrats' fretting over Obama's perceived disadvantages among working-class whites in 2008, for which the rust-belt states are known. And it surely resonates for any Republican who remembers news outlets calling Ohio on Election Night, ensuring Obama's win and prompting thousands to gather outside the White House to cheer the GOP's defeat, taunt president George W. Bush and wave open containers.

But could Santorum really win those states? And if not, could any Republican? A new poll casts doubt on both questions.

Despite representing Pennsylvania in Washington for 16 years, Santorum is not very popular in his home state among all survey respondents - not just Republicans - Quinnipiac University finds in its latest round of polling, released on Wednesday. Indeed, he's less popular than Obama.

In Quinnipiac's poll, 45 percent of Pennsylvanians said they view Santorum unfavorably while only 37 percent said they view him favorably. Obama, by contrast, is popular (48 percent favorable/46 percent unfavorable), Quinnipiac finds.

In a putative general-election matchup, Obama defeats Santorum 48 percent to 41 percent, according to Quinnipiac.

In Ohio, the same is true: Santorum is unpopular (37 percent unfavorable/33 percent favorable), and again Obama is popular (49 percent/46 percent). Obama would defeat Santorum in the general election, 47 percent to 40 percent, Quinnipiac finds.

Mitt Romney fares better than Santorum in Quinnipiac's polling, but Republicans might find the numbers discouraging. Romney is narrowly unpopular in Pennsylvania (38 percent unfavorable/37 percent favorable) and even less popular in Ohio (43 percent unfavorable/36 percent favorable), and he loses to Obama head-to-head in both states - by three percentage points in Pennsylvania and by seven in Ohio.

Of course, much can change between now and November. For one, the fate of Obama's health-care law, the signature policy initiative of his first term, hangs in the balance as a gigantic political variable.

But despite Santorum's steel-town upbringing, working-class economic pitch and social-conservative agenda, the numbers don't reveal him as a rust-belt champion for the GOP. And despite Romney's wins in Michigan and Ohio, which might have beat back the idea that he struggles in relating to the working class, he doesn't look like a Republican savior in the Midwest, either.