According to a Quinnipiac University Polling Institute poll of registered voters released on April 15, 2010, Mr. Rubio now leads Gov. Crist in the Republican primary for U.S. Senate by 56 percent to 33 percent, with 10 percent undecided. The poll also found that the approval rating for Gov. Crist's performance in office was at his all-time low of 49 percent, and his disapproval rating was at an all-time high of 39 percent.

Among registered Republicans, Mr. Rubio had a strong lead on the questions of who is more trusted to do in office what he promises on the campaign trail (54 percent to 30 percent), who most shares the respondent's values (56 percent to 32 percent), and who is the more consistently conservative (59 percent to 27 percent).

The poll identified what may be viewed as a gender gap. Republican men favored Mr. Rubio by 63 percent to 28 percent, while Republican women favored Mr. Rubio by 49 percent to 39 percent.

In a two-way general election race against the presumptive Democratic candidate, U.S. Rep. Kendrick Meek (D-17th Congressional District), the poll indicated that either Gov. Crist or Mr. Rubio would win. The results of the Crist-Meek matchup gave Gov. Crist 48 percent to Rep. Meek's 34 percent, with 14 percent undecided. The Rubio-Meek matchup showed 42 percent for Mr. Rubio, 38 percent for Rep. Meek, and 17 percent undecided.

The Quinnipiac poll also is the first public poll to ask about a hypothetical three-way race, with Gov. Crist running as an independent. In that matchup, Gov. Crist has the support of 32 percent of respondents, Mr. Rubio has 30 percent, Rep. Meek has 24 percent, and 13 percent are undecided.

The poll of 1,250 registered voters, including 497 registered Republicans, was conducted from April 8 through April 13, 2010. The margin of error is 2.8 percentage points for the general questions and 4.4 percentage points for the Republican-only questions.

The primary results are consistent with a poll released by Rasmussen Reports on April 12, 2010. In that poll of likely Republican voters, Mr. Rubio leads Gov. Crist by 57 percent to 28 percent. Gov. Crist is viewed very favorably or somewhat favorably by 55 percent of respondents, with 44 percent of respondents viewing him very unfavorably or somewhat unfavorably and one percent not sure. Of the respondents, 72 percent view Mr. Rubio very favorably or somewhat favorably, while 19 percent view him very unfavorably or somewhat unfavorably and nine percent are not sure.

The Rasmussen survey of 500 Republican likely voters was conducted on April 8, 2010 and has a margin of error of 4.5 percentage points.