A new poll shows Marco Rubio slipping ahead of Gov. Charlie Crist in the U.S. Senate race for the first time.
It also suggests that Rep. Kendrick Meek of Miami is turning around his race against Palm Beach real estate investor Jeff Geene in the Democratic Senate primary, moving to a double-digit lead after trailing Greene by substantial margins for the last several weeks.
The poll also indicates that Crist, a no-party candidate, is heavily dependent on support from Democrats, and if Democratic voters move toward a nominee of their own party, Crist's support will erode.
Crist has long been unusually popular among Democratic voters -- black voters in particular -- for a lifelong Republican.
But the new poll results show he may have trouble hanging onto enough Democratic voters to make up for the loss of GOP support caused by his move away from the Republican Party.
• With Meek as the Democratic nominee, the poll shows Rubio, a Republican, leading a three-way race against Meek and Crist by a statistically significant margin -- Rubio 38 percent, Crist 33 percent, Meek 18 percent and 11 percent undecided.
• With Greene as the Democratic nominee, Crist remains in first place, but by a margin so narrow it's a statistical tie -- Crist 39 percent, Rubio 38 percent, Greene 12 percent and 11 percent undecided.
• In the Democratic primary, Meek leads Greene by 40 percent to 26 percent, with 6 percent choosing other candidates and 28 percent still undecided.
The poll was done for a group of news media clients by Mason-Dixon Polling & Research, considered by many political insiders to be the most reliable company that publishes Florida political polls.
It included interviews with 625 likely voters Monday through Wednesday , with an error margin of 4 percentage points; the Democratic primary questions, with a smaller sample, would carry a 5-point error margin.
A May Mason-Dixon poll showed Crist with a significant lead in a matchup against Rubio and Meek - 38 percent to Rubio's 32 percent and Meek's 19 percent.
Most other recent polls have also shown Crist maintaining a lead in the general election matchup.
Prior to this poll, the average of polls reported on the Real Clear Politics Web site gave Crist an advantage of 4.5 points in the race.
Crist appears to be suffering from "tying himself close to President Obama on the economic stimulus plan and the Gulf oil spill clean-up efforts," said pollster Brad Coker of Mason-Dixon.
In the aftermath of the spill, approval numbers for both Obama and Crist have dropped. A section of the poll released Friday showed approval of Crist's performance as governor hitting their lowest point ever; today's numbers showed voters' favorable opinions of him also declining, to 39 percent.
How Florida's Democratic voters react in the unusual three-way race as the Nov. 2 general election nears is likely to be the deciding factor, said pollster Brad Coker of Mason-Dixon.
Crist has said that he thinks his support in the Senate race comes about equally from Democrats and Republicans, but the new Mason-Dixon poll shows him heavily dependent on Democratic support. Of those who backed him, 61 percent were Democrats, 16 percent were Republicans and 23 percent no-party or minor-party voters.
Can Crist hang onto those Democratic voters? He's still the most popular of the three candidates among Democratic voters, but his lead is narrowing, Coker said.
If Greene is the nominee, Crist gets 61 percent of the Democrats.
With Meek in the race, 45 percent of the Democrats polled supported Crist, 36 percent back Meek and 7 percent back Rubio.
If Meek wins the Democratic nomination, Coker said, it's likely to increase his share of the Democratic vote, "probably drawing some of it away from Crist."
Meek, who would be Florida's first elected black senator, also is likely to draw black voters away from Crist if Meek becomes the nominee and raises his profile.
In this poll, Crist drew 19 percent of black voters - but, Coker said, it's questionable whether Crist can continue to draw that percentage in a race against Meek.
Rubio, meanwhile, is solidifying his grip on Republican support in the race. Among Republicans polled, 71 percent favored Rubio compared to 14 percent for Crist.
In a three-way general election race, Coker noted, a candidate could win with as little as 34 percent of the vote, if the other two candidates split the remaining vote evenly.
But, Coker noted, "With Crist currently at 33 percent and questions about his ability to hold Democratic and African-American support if Meek wins the primary, it will be tough for Crist to thread that needle."