Reeling Republicans suffered another body blow this past weekend when Florida reported a surge of new Democratic registrations, mirroring similar gains nationwide.

Between January and May, Democrats added 106,506 voters to their ranks, while Republicans signed up just 16,686. In South Florida’s Broward County — the second biggest in the state — Democratic registrations were up 6.7 percent, while Republicans grew by just 3 percent. And in Miami-Dade, the most populous county, Democrats outregistered Republicans 31,000 to 2,000 between January and June.

While the Sunshine State registration boom will undoubtedly shine on the Obama campaign, the South Florida numbers should be extremely worrisome to Cuban-American Republican Reps. Mario Diaz-Balart, Lincoln Diaz-Balart, and perhaps even Ileana Ros-Lehtinen.

The first independent polling of these races points to unmistakable discontent. Although polling by Bendixen & Associates gave Ros-Lehtinen a comfortable 58-31 lead over Democratic challenger Annette Taddeo, the Diaz-Balart brothers are clearly in trouble. Both won with nearly 60 percent of the vote in 2006, yet their Democratic opponents are raising significant sums. And the polling looks bad, too. Mario leads Democratic challenger Joe Garcia just 44-39, while Lincoln leads Democrat Raul Martinez by an even narrower 41-37 margin, meaning that both clocked in well under 50 percent. Failure by an incumbent to poll at or above 50 percent in a reelection poll this early suggests trouble ahead. As a result, the Democratic Congressional Campaign Committee has added both Garcia and Martinez to its “Red to Blue” list of top targeted races.

Democrats have been resurgent in the region, as the voter registration numbers attest. In 2006, Democrats picked up two House seats in the area, and last year, a Cuban-American Democrat surprisingly picked up an open state legislative seat in Ros-Lehtinen’s congressional district.

Politically, district voters are less Cuba-obsessed than their hard-line elders, and younger Cubans are less concerned about the Castro regime than they are about rules that limit them from financially helping or visiting their families. For a Latino culture that places the family above all else, there is no worse sin than getting in the way of relatives — and the Diaz-Balarts and Ros-Lehtinen have been the premier supporters of this gross violation of family values.

The realization that such policies must change is sweeping over the Cuban-American community, softening the ground for further Democratic advances. At a speech at the hard-line Cuban American National Foundation several weeks ago, the organization’s membership received Obama with a standing ovation, applauding the candidate’s call to end the anti-family provisions and engage in dialogue with the island’s leader, Raúl Castro.

Invited to speak to the organization, the McCain campaign sniffed: “It is obvious they have chosen, they have embraced, they have given a welcome and a forum to Barack Obama — a man who wants to sit down with Raúl Castro without preconditions … So I don’t understand the insistence of the gentlemen in the Cuban American National Foundation in wanting to get together with John McCain when John McCain doesn’t want to get together with them.”

As usual, John McCain is a man living in the last century, just like the dwindling pack of anti-Castro dead-enders obsessed with a vendetta, rather than the health of the country they left behind. At long last, regional voters appear eager to join the rest of the United States in moving ahead rather than indulging resentments two generations old.

Disclosure: Daily Kos has added Joe Garcia to its fundraising efforts.

Moulitsas is founder and publisher of Daily Kos .