From NBC's Mark Murray
First Read confirms the news that Mitt Romney is endorsing Florida GOP Senate candidate Marco Rubio. A source close to Romney tells First Read that the possible Republican presidential candidate is expected to appear at a campaign event for Rubio on Monday in Tampa, FL.
The endorsement shouldn't come as much of a surprise. For one thing, Rubio is leading primary opponent Charlie Crist by 23 percentage points, according to a recent Quinnpiac poll. In addition, there has been a tremendous amount of speculation -- which Crist isn't totally knocking down right now -- that the Florida governor might run as an independent or even quit the Senate race altogether.