By Rachel Kapochunas, CQ Staff

Lincoln Diaz-Balart and Mario Diaz-Balart are brothers who represent neighboring U.S. House districts in south Florida. They both are Republicans, and have benefited from the fact that their Hispanic-majority districts have large numbers of their fellow Cuban-Americans, a group heavily drawn to the GOP because of a shared antipathy to Fidel Castro and the communist government he established and long dominated. In fact, neither Diaz-Balart has had to worry much about general election competition from Democrats in their districts — until this year.

Democratic strategists, who captured two other south Florida districts in their successful 2006 campaign for control of the House, are targeting both of the brothers’ districts this year, and they have recruited prominent Cuban-American figures as their challengers. Raul Martinez — the Democratic former mayor of Hialeah, the 21st District’s largest city — is waging a campaign against eight-term incumbent Lincoln Diaz-Balart . Joe Garcia, former executive director of the Cuban American National Foundation, is running against three-term member Mario Diaz-Balart in the 25th District.

Although both of the brothers Diaz-Balart look highly likely to win in November, the stepped-up effort by the Democrats in the 21st District and 25th District has prompted CQ Politics to change its ratings on both races to Republican Favored from Safe Republican.

The fact that the Democrats are even taking serious looks at these districts denotes a sharp change in attitude among that party’s officials. The personal popularity of Lincoln and Mario Diaz-Balart and the Republican affinities of many Cuban-Americans had led Democrats to perceive both as almost untouchable.

Lincoln Diaz-Balart ’s easy win in 2006, by 19 percentage points, over unheralded Democratic candidate Frank J. Gonzalez marked only the second time in his eight House general elections in which he faced any Democratic opponent. Mario Diaz-Balart took 65 percent of the vote in his initial 2002 House election to defeat Democratic state Rep. Annie Betancourt, another Cuban-American; ran unopposed in the 2004 general election; then defeated Democrat Michael Calderin by 17 points in 2006.

Lincoln Diaz-Balart , who was born in Havana in 1954, has served in Congress since his first election in 1992. Seventy percent of his constituents are Hispanic, making the 21st District the eighth most Hispanic district in the nation by percentage of total population.

Martinez is working from a political base in Hialeah, a heavily Hispanic city in Miami-Dade County that contributes roughly 210,000 of the 21st District’s residents.

“I guess Raul Martinez is counting on splitting the vote in Hialeah with Lincoln Diaz-Balart , even though Hialeah is overwhelmingly Republican, and then winning the rest of the district where the Democrats are a little bit stronger, the northern part of the district, which is in Broward County,” said Kevin A. Hill, an associate professor of politics at Florida International University in Miami.

Hill said that “on paper,” younger brother Mario — who was born in Ft. Lauderdale in 1961 — would appear to have a more difficult re-election race, as Republicans have a smaller registration edge in his 25th District than in the 21st. But Hill said other factors are influencing this year’s contest.

“In a perfect world for him [Lincoln] it would be very difficult for him to lose that seat because it’s pretty Republican,” Hill said. “However, in the real world, Lincoln’s got a much more viable opponent than Mario.”

But Hill noted that Martinez is not without his own challenges. Martinez was convicted of extortion, racketeering and conspiracy in the early 1990s and sentenced to prison. The charges were dropped on appeal. Martinez now runs a public relations firm.

Hill described Martinez as a “very polarizing figure” who is well-known to be at odds with the Diaz-Balarts.

The 25th District that Mario Diaz-Balart represents encompasses western Miami-Dade County and is 62 percent Hispanic. Garcia, his opponent, will emphasize his longtime activism in Cuban-American affairs to try to cut into Diaz-Balart’s core constituency, while utilizing his strong ties to the Democratic Party establishment to build a campaign infrastructure. Garcia was elected as chairman of the Miami-Dade Democratic Party in 2006 and served as director of the New Democrat Network’s Hispanic Strategy Center.

Joe Trippi, who ran former Vermont Gov. Howard Dean’s 2004 presidential campaign and was an adviser to former North Carolina Sen. John Edwards in his bid for the 2008 Democratic presidential nomination, has signed on as Garcia’s senior media adviser.

Yet the Democratic contenders in both districts appear to face formidable partisan odds. Both districts supported President Bush’s 2004 re-election bid by nearly equal margins. The 21st gave Bush 57 percent of the vote and Bush received 56 percent in the 25th.

This year’s races in these districts will be watched to see if there are any variances in Cuban-Americans’ partisan tendencies in light of the recent decision of Fidel Castro, who has been seriously ill, to step aside and allow his brother Raul Castro to take power.

But Hill said that the absence of Fidel Castro in office does not alter the local dialogue. “Fidel Castro could be dead in the ground and he’d still be the number one issue in local politics,” Hill said.

The Diaz-Balarts also have a head start on fundraising. Lincoln reported $904,000 on hand as of Dec. 31 and Mario reported $466,000 on hand. Neither of their challengers has yet filed a report with the Federal Election Commission, with the next deadline on April 15 for campaign finance activity through March 31.

Technology manager Dean Santoro has filed to run in the Republican primary against Lincoln Diaz-Balart in the primary but has not yet filed a campaign finance report. May 2 is the candidate filing deadline for the state’s Aug. 26 primary.

The state Republican Party has stepped into the races in both districts already, putting out press releases criticizing Garcia and Martinez. The party also recently established a Director of Congressional Affairs to “focus full time” on ensuring the re-elections of the party’s incumbents in their state, in which 16 of the 25 current House members are Republicans.