Guess who's worried about losing Pennsylvania?

After a Saturday visit by Paul Ryan to the central part of the state and a scheduled Sunday campaign stop by Mitt Romney to the Philly suburbs, the Obama campaign wants to phone-a-friend.

How worried is Obama about losing the Keystone State? Enough to call in Bill Clinton to shore up his sagging campaign in Pennsylvania.

The Obama campaign announced late Saturday (I'm talking really late - nearly 11 p.m. Saturday) that Clinton would make four campaign stops for Obama in Pennsylvania on Monday.

That's a lot of campaigning by the former president with a bad heart on behalf of the current occupant of the White House.

President Clinton will speak at rallies for the Obama-Biden ticket in Philadelphia, Blue Bell, Pittsburgh and Scranton.

Why the panic?

In addition to the surprise visit by Romney to Bucks County on Sunday, the Republican National Committee announced a $3 million TV ad buy in Pennsylvania. The Karl Rove-backed super PAC American Crossroads also launched a major TV ad campaign in Pennsylvania last week.

Obama's road to re-election could collapse in Pennsylvania if he doesn't carry the state on Tuesday.