Rasmussen:

Republican Congressman Connie Mack changed his mind late last month about challenging longtime Democratic Senator Bill Nelson in 2012, and now he finds himself with a modest edge over the incumbent in the first Rasmussen Reports telephone survey of Florida's U.S. Senate race.

The latest statewide telephone survey of Likely Voters in the state shows Mack with 43% to Nelson's 39%. Five percent (5%) prefer some other candidate, and 13% remain undecided. (To see survey question wording, click here.)

Mack, who has served in the House since 2005, initially said he would not challenge Nelson's reelection. However, the son of a former senator and husband of Congresswoman Mary Bono Mack announced his candidacy after the GOP field thinned. Nelson has served as congressman, treasurer and senator for Florida in a political career stretching back to the early 1970s.

Nelson leads another Republican challenger, Congressman Adam Hasner, 40% to 31%. Nine percent (9%) prefers some other candidate in the race, while 19% are not sure.

Nelson picks up 39% against former Senator George LeMieux, who draws support from 33%. Ten percent (10%) like some other candidate given this matchup, and 18% are undecided.

Among voters not affiliated with either party, Mack draws 38% of the vote, while Nelson is backed by 35%. Nelson holds a small lead over the other two GOP contenders among unaffiliated voters.

Rasmussen Reports polling also shows Senate races in Missouri, Wisconsin and Virginia to be close.

Mack's late arrival in the race has been a godsend for the GOP in Florida. None of the other Republican challengers had been able to make much of a dent in Nelson's incumbency.

But Mack, scion of a powerful political family in Florida, has automatic name recognition and an excellent record in the House in his own right. It's not going to be easy - Nelson has proven himself a survivor through the years and an is excellent campaigner and fundraiser. But Mack gives Republicans a solid opportunity to take a seat away from the Democrats and help build a GOP majority in the senate.