By Rachel Kapochunas, CQ Staff

Florida Republican Jeb Bush, a popular figure as governor of Florida from 1999 to 2007, announced Tuesday that he will not be a candidate in his state’s 2010 open-seat Senate race.

The announcement by Bush — President George W. Bush ’s brother — will disappoint fellow Republicans who viewed him as their dream candidate for the seat that one-term Republican Sen. Mel Martinez is leaving open to retire. But Bush’s opting out opens the door for a broad field of potential Republican candidates, some of whom have expressed interest in the contest but said they would defer to Bush if he decided to run.

“While the opportunity to serve my state and country during these turbulent and dynamic times is compelling, now is not the right time to return to elected office,” Bush said in a statement. Bush cited a desire to play a role in “rebuilding” the Republican Party, focusing on “core conservative principles,” after the major electoral setbacks it has suffered over the past two election cycles.

The announcement came just two days after Fox News Channel aired an interview with his father, former President George H.W. Bush, who said of Jeb Bush, “He’d be an outstanding senator. This is a guy that really has a feel for people, the issues in Florida and nationally.” The elder Bush also said he hoped Jeb Bush would someday follow him and George W. Bush in the White House, calling him “as qualified and as able as anyone I know in the political scene” to be president.

Former state House Speaker Marco Rubio, seen as a top-tier prospect for the Republican Senate nomination with Bush out of the running, wrote in an e-mail message to CQ Politics that he spoke with Bush and will make his own decision regarding the race in the coming weeks. He added that he has taken the step of establishing a Web site in preparation for a possible campaign.

Rubio will certainly have company in mulling what now bodes as a wide-open race. Among those who have indicated interest is state Attorney General Bill McCollum, a former U.S. House member who lost to Democrat Bill Nelson in 2000 as the Republican Senate candidate and then lost to Martinez in the 2004 Republican primary for the seat left open that year by the retirement of Democrat Bob Graham.

Republican House members whose names have been floated include Connie Mack — the namesake son of a former Florida Republican senator — who just began his third term in the 14th District, and Vern Buchanan , now a second-term incumbent in the 13th District. Jeff Atwater, recently chosen as state Senate president by his colleagues, also is often cited as a Republican contender, though his office last month said his focus remained on his legislative duties. Former state House Speaker Allan Bense, who considered entering the 2006 race to challenge Democratic Sen. Nelson but backed off, continues to be mentioned as a potential candidate.

Democrats, meanwhile, say they will make the Florida race a priority in light of recent gains that stemmed a long-running Republican trend in the state. These include Democrat Barack Obama ’s victory over Republican John McCain in the 2008 presidential race and the party’s net gain of two House seats over the past two election cycles, trimming the GOP’s edge from 18-7 to 15-10. The seat that will be contested in 2010 went to Republican Martinez by a margin of just 1 percentage point over Democrat Betty Castor, the state’s former education commissioner.

“It is clear that Florida will be a central battleground in the 2010 election,” state Democratic Party Chairwoman Karen Thurman said in a statement following Bush’s public announcement.

Topping the list of Democratic Senate prospects is state chief financial officer Alex Sink. Strategists indicate that Sink, whose office is the equivalent of state treasurer, has the ability to clear the Democratic field if she decides to run, but she has yet to indicate her campaign plans. Reps. Allen Boyd of the 2nd District, Kendrick B. Meek of the 17th District and Ron Klein of the 22nd District also have been discussed as possible contenders for the Democratic nomination, as well as state Sen. Dan Gelber.

The wheels for these political machinations began on Dec. 2 when Martinez announced that he would not run in 2010 for a second term. Although he pulled out a narrow victory in 2004, his hard-hitting campaign tactics left him with tepid public approval ratings. His support base shrunk further because of his close ties to President Bush, whose own popularity dropped sharply after his re-election in 2004: Martinez served as secretary of Housing and Urban Development during Bush’s first term and later did a brief stint as general chairman of the Republican National Committee at Bush’s behest.

Correction: The Democrats’ net gain in Florida U.S. House seats over the past two election cycles is three, trimming the Republican advantage from 18-7 to 15-10.

First posted Jan. 6, 2009 5:46 p.m.