Harris Mullen, the founder and publisher of Florida Trend, once wrote that he didn’t recall seeing a white Republican in Florida until the late 1930s, when he was about 14. By 1968, however, his world had changed dramatically. “All the black people have switched from Republican to Democrat, Florida is a two-party state and the Baptists are dancing and smoking cigarettes in public,” Mullen wrote at the time.

Only recently has the Republican drift moderated, with many describing Florida today as a “purple” state where a large swing-vote contingent can push the state into either camp.

How might Florida’s political landscape look a half-century from now? Here are several demographic trends that offer a clue.

Trend 1: The Graying Electorate

Florida’s electorate is divided more or less evenly among young, middle-aged and older voters. Over the next 10 to 20 years, however, Florida’s senior population is predicted to rise dramatically. While approximately 17.6% of Florida’s population was 65 or older in 2000, more than one in every four residents (27.1%) of Florida will be 65 or older by 2030, according to Census estimates.

Those seniors “may be a different kind of retiree,” says Susan MacManus, a political science professor at the University of South Florida. Should the Baby Boomers squander their wealth, she says, they would be “different than the older people moving here over the last 20 to 30 years who’ve been more affluent than older people in general.”

One question is whether so many new seniors will create political friction along generational lines. Grant Thrall, a University of Florida professor who specializes in business geography, suspects the political parties will try to straddle any potential division. “I don’t see one party becoming the party of the elderly and the other becoming the party of the young, but within each party, at their conventions, and perhaps within their legislative caucuses, there’s going to be frictions between people who represent large elderly districts and those who don’t.”

Neither party has a lock on Florida’s senior vote anymore. Baby Boomers, who range from 44 to 62, are more concerned about Social Security and Medicare than elderly voters are, polling suggests.

Lifestyle tends to be a better predictor of voting habits than age, and one thread that seems to run through both Baby Boomer and elderly voters is concern about crime and children. “There’s tremendous worry about the economic and moral future of their grandchildren. I hear this all the time when I speak to Rotary clubs,” says MacManus.

Trend 2: More Newcomers

Waves of new immigrants will continue to shake up the political scene over the next several decades.

Of particular note is the fact that Florida’s Hispanic community is becoming more diverse. While Cuban-Americans still comprise the largest Hispanic population in Miami-Dade County, the county also has sizable populations of Nicaraguans and Colombians. In Broward County, Puerto Ricans are the largest Hispanic group. In Jacksonville, Tampa Bay and Orlando, Puerto Ricans and Mexicans are the largest “subgroups,” but those regions also are home to significant numbers of Hondurans, Venezuelans, Ecuadorans and Argentinians.

The biggest difference between the earlier generations of Cuban immigrants and newer, non-Cuban immigrants is that the non-Cubans are less concerned with foreign policy and more concerned with domestic issues like education and jobs.

Though neither party has a lock on these voters, new immigrants are helping to make the Democratic Party more competitive in the state, says James Gimpel, a University of Maryland professor who has written extensively about Florida’s changing electorate in his book “Patchwork Nation: Sectionalism and Political Change in American Politics.” “Many of these Latino immigrants move into the Democratic Party. A lot of the Cold War politics associated with the Cuban migrations — that’s fading,” says Gimpel.

Indeed, the number of Hispanic voters registered as Democrats has overtaken the number of Hispanic Republicans, according to recent Florida voter registration statistics. A Democratic Party analysis provided to the Miami Herald in May showed 418,339 Hispanics Democrats statewide, compared to 415,068 Hispanic Republicans. The remaining 345,108 Hispanic voters did not register their affiliation with either party.

Thrall says political forecasters shouldn’t focus exclusively on Hispanic immigrants when examining immigration trends. Thrall predicts that in 20 to 30 years, the economies of Latin America will strengthen and fewer Latin Americans will move to Florida and the U.S. in general. “Miami will continue to be a major financial center for Latin America,” and the Latin influence in Florida won’t diminish, he says.

In 15 years, Thrall predicts, the biggest wave of immigrants will come from the Middle East and Africa. An increase in Muslim immigration to the U.S. could trigger the same sort of socio-political unrest that Germany and France have endured. “It’s going to be a major political issue in Florida in a dozen years or more, as it is in Europe today,” he says.

Trend 3: Young Professionals

Over the past couple of decades, Florida has been a magnet for young professionals who have mostly identified themselves as independents.

During the last three elections, however, the younger voters are trending heavily Democratic. History, MacManus says, shows that a realignment of the electorate can be triggered by any one of three specific events: War, an economic downturn or large-scale corruption. With two of the three triggers now present, MacManus wonders whether the recent tendency of Florida’s young professionals to register as Democrats might portend a permanent political shift by that group.

To be sure, Sen. Barack Obama’s presidential candidacy has driven some of the recent surge in Democratic registration among Florida’s younger voters. Regardless of why young voters are suddenly moving to the left, it appears to bode well for the Democrats’ long-term fortunes. History shows that over the course of their lifetimes, voters tend to stick with their initial party affiliation. Says MacManus: “If Obama wins, the younger electorate, which is already trending Democratic in Florida, could result in Florida having a rebirth of Democratic clout in the state Capitol.”