From Public Policy Polling:
PPP's first likely voters poll of Florida finds that it's likely to take its customary place as one of the most closely contested states in the country this year. Barack Obama leads Mitt Romney by the slightest of margins, 48-47, but Romney would take a small advantage in the state if he added either Marco Rubio or Condoleezza Rice to his ticket.
Obama and Romney are holding their party bases at basically equal levels, with 84% of Democrats supporting Obama and 83% of Republicans committed to Romney. Romney's holding a 47-40 lead with independents. Obama's up 51-44 with women, 61-34 with Hispanics, and 58-35 with young voters while Romney's ahead 50-45 with men, 56-39 with whites, and 52-44 with seniors.
We tested five potential running mate pairings for Romney in Florida and two of them moved him from a small disadvantage to a small lead. Home state Senator Marco Rubio makes the biggest difference for Romney, pushing him up to a 49-47 lead. Rubio's approval numbers aren't earth shattering at 45/42, but his appeal is strong enough to help Romney gain a couple points with both Democrats and Republicans.
The other difference maker among potential Romney running mates is Condoleezza Rice. She has a 59/28 favorability rating, basically unheard of among politicians today. Republicans (76/15) and independents (62/26) and love her and even with Democrats she's on narrowly positive ground (42/41). If she was on the ticket Romney's lead with independents would jump from 7 points to 13, leaving him ahead 46-45 overall.
The other trio of potential Romney running mates has minimal impact or pushes the race slightly in Obama's direction. With Tim Pawlenty on the ticket Obama's lead remains at a point, with Bobby Jindal on it Obama's lead goes up to 3, and with Rob Portman on it he maximizes his advantage at 4 points. Jindal has 58% name recognition in Florida, Pawlenty's is 56%, and Portman's is 45%.
Regardless of who Romney picks it looks like Florida is once again a sheer toss up, and there's not much reason to think that will change between now and November.