Thursday, Quinnipiac released a series of “swing state” polls that showed how much danger Barack Obama faced in Ohio, Pennsylvania, and Florida, even with the Republican Party fighting through its primary season.  Obama has lost the independents he assiduously courted in 2008, and the voters that at one time were called Reagan Democrats are fleeing the ticket.

So what could bring them back? A little change in the bottom of the ticket.  Survey USA conducted a poll in Pennsylvania — which is a must-win state for Democrats in any presidential election — with two models for Democrats: An Obama-Biden ticket and an Obama-Hillary Clinton ticket.  They ran the numbers against two models of a Republican ticket of Mitt Romney and Newt Gingrich in both positions on the bill.  Head to head with just the top position in play, Obama beat Gingrich by only seven points (47/40) and fell into a tie with Romney (44/44).  Add the running mates, however, and the differences in Democratic support were rather striking:

* Democratic ticket of Obama-Biden 46%
* Republican ticket of Romney-Gingrich 45%

* Democratic ticket of Obama-Clinton 50%
* Republican ticket of Romney-Gingrich 41%

* Democratic ticket of Obama-Biden 46%
* Republican ticket of Gingrich-Romney 42%

* Democratic ticket of Obama-Clinton 50%
* Republican ticket of Gingrich-Romney 40%

The swing is significant in both models when adding Hillary to the ticket.  Survey USA explains one reason why:

The Obama-Biden ticket gets 49% of female votes against both Republican tickets, Romney-Gingrich and Gingrich-Romney. But, an Obama-Clinton ticket gets 57% of the female vote against both tickets. Said another way: With Biden on the ticket, Obama carries PA women by an average of 10 points. With Clinton on the ticket, Obama carries PA women by an average of 23 points.

Don’t forget that Obama added Joe Biden to the ticket in the first place to help in states like Pennsylvania and Ohio, as well as to fill a foreign-policy gap that got highlighted in the Russian invasion of Georgia just before the conventions in 2008.  Biden claims Pennsylvania as his native state.  Yet the results in the Keystone State show that Biden isn’t providing any bump for Obama, even if he’s not hindering him either.

It’s not just a gender gap, either.  An Obama/Hillary ticket, rather than one including Biden, wins back two age demographics over a Romney/Gingrich ticket: 50-64YOs go from 43/47 to 49/45, and seniors go from 43/49 to 47/46.  There is a narrow shift among both black (76/18 to 82/14) and white (43/47 to 46/45) voters as well.  There is even a shift among self-identified Tea Party supporters, from 18/76 to 24/69.

Readers should keep a couple of caveats regarding this poll in mind.  The unknowns are not so much whether Hillary would agree to be Obama’s running mate, but the assumptions of the Republican ticket.  Neither of the two mentioned may make it to the general election.  Even with the tickets as shown, Republicans have not yet united behind a candidate, and the numbers for Obama as an incumbent in a state with an overwhelming Democratic registration advantage are not impressive.  Also, the sheer novelty of replacing a sitting VP on a re-elect ticket (it hasn’t been done since FDR booted Henry Wallace in 1944 to distance himself from Wallace’s shift towards neo-Stalinism) could damage Obama everywhere else by making him look weak and desperate.

But those caveats don’t erase the impact that a running-mate switch might have in traditional Democratic interior states for an incumbent with no other real story to tell.  While these changes don’t look overwhelming, they would be enough to push Pennsylvania back into the Democratic column in a close election.  And if it came down to rescuing Pennsylvania with no appreciable downside of a Biden retirement, Democrats might want to draft Hillary to rescue Pennsylvania — and perhaps a few other faltering Democratic strongholds as well, like Michigan.