Those who argue that the long slog of the Republican nomination race has hurt the chances to defeat Barack Obama will have new ammunition from Rasmussen’s poll of likely general-election voters in Florida.  Obama has narrow leads against both Mitt Romney and Rick Santorum in the key swing state — but within the margin of error, and nowhere near the 50% level incumbents usually need to feel safe:

President Obama now runs just barely ahead of both Republican front-runners in the key electoral state of Florida.

A new Rasmussen Reports telephone survey of Likely Florida Voters finds Obama leading former Massachusetts Governor Mitt Romney 46% to 43%. Seven percent (7%) like some other candidate, and four percent (4%) are undecided.  (To see survey question wording, click here.)

In a face-off with former U.S. Senator Rick Santorum, Obama posts a 45% to 43% lead. Eight percent (8%) favor someone else in the race, while four percent (4%) again remain undecided.

This marks basically no change in the Obama-Romney matchup from a month ago when the president also led by three points, 47% to 44%.  Santorum at that time was in a near tie with the incumbent with Obama earning 47% to the GOP hopeful’s 46%.

While it obviously would be better to have both Republicans leading Obama at this point, keep two points in mind.  Head-to-head polls while only one side has a competitive primary in process is an apples-to-oranges comparison.  The Republican voting bloc is split, and a true comparison won’t be possible until after one candidate gets the nomination.  Also, an incumbent polling at 45-46% is actually a weak candidate.  Voters know that candidate already, and their upside is usually pretty limited once the campaign gets underway.  That level isn’t low enough to be a sure loser in a general election, but it’s low enough to be seriously at risk for a loss.

The internals are rather interesting, although the sample is potentially an issue.  The D/R/I in this poll is 31/35/31, while the exit polling from Florida’s 2010 Senate race was 36/36/29.  It’s possible that Republicans will be more enthusiastic than Democrats in the general election, but a dropoff of five points might be assuming a little too much.

Otherwise, there are problems for both sides in the internals.  Obama has a double-digit lead over both Republicans among women and a wide lead among the 18-39YO age demo.  However, that bloc tends to have poor turnout, and while the lead is large, Obama only get to 56% and 57% over Romney and Santorum, respectively.  Both men score majorities over Obama in the 40-64YO and senior demos, with Romney doing especially well among the latter (62/33).  However, independents in Florida break hard for Obama in both matchups, 55/31 against Romney and 50/31 against Santorum.  Party loyalty is consistent for both matchups and both Republican candidates.  Perhaps the most worrisome internal for the GOP will be the Hispanic vote, which breaks heavily to Obama against Romney (51/24) and Santorum (57/12).

Florida is a key state for both parties.  The GOP probably can’t win the White House without it, and Obama would have a difficult time winning his re-election while losing the Sunshine State.  Republicans need to find a way to put Florida away as soon as possible.