Republican Marco Rubio “is in the catbird’s seat” in the race for Florida’s U.S. Senate seat, with Gov. Charlie Crist stalled in second and Democrat Kendrick Meek lagging even further behind in third, according to a Mason-Dixon poll released Thursday.

Rubio has pushed his lead to 15 percentage points, attracting 42 percent of voters, compared to 27 percent for Crist, who’s running as an independent, and 21 percent for Meek, the poll showed. Ten percent of voters remain undecided.

If Rubio can stay above 40 percent, it will be difficult for Crist or Meek to catch him, said Mason-Dixon pollster Brad Coker.