In more swing-state news, a new Rasmussen poll in Florida maintains the Mitt Romney momentum narrative — albeit narrowly.  For the first time, Romney has broken through the majority barrier to take a small four-point lead over Barack Obama, 51/47:

Mitt Romney has crossed the 50% mark for the first time to widen his lead to four points in Florida.

The latest Rasmussen Reports telephone survey of Likely Florida Voters finds Romney with 51% support to President Obama’s 47%. Two percent (2%) remain undecided. (To see survey question wording, click here.)

This is the widest gap between the candidates in surveys this year, but Florida remains a Toss-Up in the Rasmussen Reports Electoral College Projections. Prior to these findings, the candidates have been within two points of each other in Florida in every survey since April. Last week, it was Romney 49%, Obama 47%.

Obama carried Florida over John McCain in 2008 by a 51% to 49% margin.

Suffolk bailed out of Florida, Virginia, and North Carolina earlier this week, but this doesn’t exactly look dominating — at least not yet.  This comes within the margin of error, if to the outer edges of it, and a lot can happen in three-plus weeks.  It’s the first time either candidate has shown any Sunshine State momentum in this poll series, but even that’s not fully substantiated in this survey.

The internals, though, look pretty devastating.  The partisan split is an R+1, almost the same as the 36/36/29 2010 midterms, but with fewer independents at 39/38/23.  The shortchanging of independents hurts Romney more than Obama, though, as Romney has a sixteen-point lead among unaffiliated voters, 54/38.  Obama won independents in 2008 by seven, 52/45, in a D+3 turnout at 37/37/29.

Similarly, Rasmussen slightly oversamples women (56%) compared to 2008 (53%).  That also doesn’t help Romney, as Obama wins women by eight points, 53/45.  However, Romney wins men by eighteen points, 58/40, for an overall gender advantage of +10.  In 2008, Obama had a gender advantage over John McCain of +9 (+4 among men and +5 among women).  That’s a nineteen-point switch in the gap.

Furthermore, Romney now leads on the two big issue questions asked by Rasmussen in this poll.  On the economy, a majority of voters trust him more over Obama, 51/45.  A majority also trusts him more on national security, but that’s within the MoE at 50/47.  Obama’s job approval is slightly under water at 48/51, but 45% strongly disapprove.

The internals paint a much more formidable picture of Romney’s strength in Florida than the topline does.  We’ll see if his momentum grows in the next poll series, but a 16-point lead among independents with three weeks to go against an incumbent looks very good for the challenger.