Matthew Dowd has some very bad news for liberals. Sarah Palin, he argues, has a real shot at winning the presidency in 2012.

Gallup polls over the past 60 years show that no president with an approval rating under 47 percent has won reelection, and no president with an approval rating above 51 percent has lost reelection. (George W. Bush’s approval rating in the weeks before the 2004 election hovered around 50 percent.) The 2012 election will be primarily about our current president and whether voters are satisfied with the country’s direction.

Who the Republican candidate is, and his or her qualifications and abilities, will matter only if Obama’s approval rating is between 47 and 51 percent going into the fall of 2012. Interestingly, in the latest Gallup poll Obama’s approval rating was at a precarious 49 percent.

Second, America is still (unfortunately) politically divided and polarized, and Palin benefits from this dynamic. While Democrats love Obama, Republicans look on him with real disfavor. The gap between Obama’s approval rating among Democrats and among Republicans is nearly 70 percentage points — a higher partisan divide than either Bill Clinton or George W. Bush experienced. Obama’s agenda and actions this year, and some mistakes, have solidified this divide.

Polls show that Palin’s favorability numbers are a mirror image of those of Obama. She is respected and loved by the Republican base, while Democrats despise her. Granted, independent voters have significant reservations about her capability to be president, and this would be a hurdle in the general election. But to win the Republican nomination, Palin needs only to get enough support from the base to win early key states. Already, in nearly every poll today, she has a level of support that makes her a viable primary candidate. Just look at the crowds and the buzz her book tour is drawing. …

Like it or not, if Sarah Palin decides to seek our nation’s highest office, she has a shot.