Johnny Carson once described St. Petersburg, Florida, as “God’s waiting room.”

The late-night comedian, who died in 2005, was making light of the city’s concentration of senior citizens, a group that dominated the politics just as they were first in line for early-bird dinners. As recently as 2008, the results were reliably Republican -- five straight mayors, a Congressman in his 20th consecutive term, a popular hometown governor.

Carson wouldn’t recognize the Gulf Coast city. St. Petersburg has been infused with a younger, more racially diverse population that is transforming its politics and serves as a broader emblem of the shift taking hold in Florida, which is considered vital to winning presidential elections, with its 29 out of the 270 electoral college votes needed to prevail.

The migration, which includes Hispanic and black voters, is driving a “fundamental political realignment” that threatens Republicans’ viability in areas where they once thrived, said Dustin Cable, a demographer at the University of Virginia’s Weldon Cooper Center for Public Service in Charlottesville.

St. Petersburg, whose population is about 245,000, elected a Democrat as mayor this month for the first time since 1975. A Democrat running for U.S. House is ahead in polls. And former governor Charlie Crist is criticizing his old Republican allies after switching parties and running for governor again, this time as a Democrat.

Turning Blue

The demographic changes are similar to those playing out in other parts of Florida. Those shifts are threatening to turn a presidential swing state into one that’s more reliably Democratic in the 2016 election and beyond.

“We either accept becoming a minority party due to demographic shifts, or we change our rules of engagement and become more successful in attracting the diverse population that’s going to be exponentially increasing in our state,” said Al Cardenas, a former chairman of Florida’s Republican party who leads the Washington-based American Conservative Union, which promotes small government.

The party still dominates the state legislature. The state is led by a Republican governor, Rick Scott, whose approval ratings haven’t topped 50 percent since he took office in 2011.

Republicans also can still see a path to presidential victory in Florida, especially if they field a home-grown talent such as former Governor Jeb Bush, brother of former President George W. Bush, or U.S. Senator Marco Rubio, who is considered a prospective primary candidate.

RNC Report

A Republican National Committee report earlier this year said the party must be more welcoming to minorities and younger voters. Party leaders are debating whether they should do that by sticking more firmly to their ideals or being more pragmatic. For instance, the party is opposed to gay marriage while a majority of young voters support it.

The demographic changes in St. Petersburg are similar to those in Northern Virginia, where a coalition of urban professionals and minorities helped President Barack Obama carry the state in 2008 and 2012. Democrat Terry McAuliffe relied on those voters to win the governor’s race on Nov. 5.

The election of Ralph Northam as Virginia’s lieutenant governor and Mark Herring’s tentative victory in the attorney general race marked the first time since 1989 that Democrats captured all three of the top state offices. Herring’s 163-vote victory will be the subject of a recount.

“This was a solidly Republican state before 2008,” Cable said of Virginia.

Hispanic Population

Florida, which Obama won in 2008 and 2012, is moving in the same direction, driven by a 67 percent increase in Hispanics since 2000, Cable said. Since 1964, only one candidate, Bill Clinton in 1992, has won the presidency without winning in Florida.

Pinellas County, home to St. Petersburg, has sided with five Republicans and five Democrats in the last 10 presidential elections.

The black population in St. Petersburg has grown to 25 percent from 22 percent in 2000, while the share of Hispanics has doubled to 8 percent from 4 percent, according to U.S. Census data. Statewide, Hispanics make up 23 percent of the population, up from 17 percent in 2000.

St. Petersburg has also gotten younger, with its median age falling from 48 in 1970 to 42 in 2010. The national median age rose from 28 to 37 during that period.

Johnny Bardine, a 34-year-old lawyer who moved to St. Petersburg in 2007, said the city has a “progressive bend” that is attracting more young Democrats like him.

Democratic ‘Resurgence’

“We’re going to see a resurgence of the Democratic party in the state,” said Bardine, who has worked on campaigns for the eight-member city council, which now has seven Democrats. “We’ll be able to trace that to what has happened in this county.”

Congressional candidate Alex Sink, Florida’s former chief financial officer and a former Democratic candidate for governor, is ahead of a Republican in polls in advance of a March special election to replace former U.S. Representative C.W. “Bill” Young, who died Oct. 18 after 42 years in office.

Mayor-elect Rick Kriseman on Nov. 5 defeated incumbent Bill Foster in a race that, while officially non-partisan, was contested by both state parties. With Kriseman’s victory, four of Florida’s five largest cities are now controlled by Democrats, including Jacksonville, Orlando, Tampa and St. Petersburg.

“What happens in St. Petersburg is pretty important on a statewide basis,” said Kriseman, 51, while knocking on doors in a predominantly black neighborhood in St. Petersburg the night before his election.

Voter Data

As Kriseman walked through a low-income neighborhood on Nov. 4, a staff member from the Florida Democratic Party held a clipboard with information about each voter, including their age, gender, party affiliation and the last time they voted.

The data-driven brand of campaigning -- and the demographic information detailed on the clipboard -- offer a glimpse into why Democrats in Florida and elsewhere see their prospects improving in advance of Congressional races in 2014 and the presidential contest two years later.

Democrats need to win a net 17 seats to gain control of the 435-member U.S. House, a prospect that party strategists say is unlikely. Democrats have identified 52 congressional districts where they want to oust Republicans, many in areas with growing minority populations, said Emily Bittner, spokeswoman for the Democratic Congressional Campaign Committee.

‘Less White’

An influx of minorities and young professionals in places such as Aurora, Colorado, California’s San Joaquin Valley and Clark County, Nevada, may endanger Republicans representing such areas, said David Wasserman, House editor of the Washington- based Cook Political Report, which tracks congressional races.

“America is getting a point less white every year,” he said. “In a number of these Republican held seats, that trend holds long-term promise for Democrats.”

When Young was first elected to Congress in 1970, Pinellas County was a “Republican stronghold” with a population of retiree-voters that helped propel the party to statewide prominence, said Susan MacManus, a political science professor at the University of South Florida in Tampa.

Sink, 65, who entered the race Oct. 30, faces a much different electorate.

Green Benches

The rows of green benches where retirees used to congregate in 1960s St. Petersburg have been replaced by condos, art museums and downtown eateries. The city’s largest private employer is financial services firm Raymond James Financial Inc.

Even Republicans say they face an uphill battle to keep the House seat they have controlled since Richard Nixon was president.

“There’s no question she’s the front-runner,” said Mike Fasano, a former Republican state representative from the Tampa Bay area. “The district has changed greatly over the last few years.”

Several Republicans, including former St. Petersburg mayor Rick Baker, declined to enter the race after Sink said she was running.

Sink could face David Jolly, a 41-year-old former aide to Young and lobbyist who is vying for the Republican nomination.

Sink, who said the “shenanigans” in Washington compelled her to run, has been pitching herself as a centrist who can break through congressional deadlock that led to a 16-day, partial government shutdown last month.

Governor Race

Crist, 57, is hoping the same message will resonate with voters as he tries to unseat Scott next year.

Crist, who left the Republican Party during a failed bid for the U.S. Senate in 2010, became a Democrat last year after saying his former colleagues had become too extreme.

During a Nov. 4 campaign rally in downtown St. Petersburg, his hometown, Crist embraced his political conversion and encouraged other Republicans to follow suit.

“So yes, yeah, I’m running as a Democrat,” he said to a crowd of about 200 supporters, including his parents. “And I’m proud to do it. But to every independent and every Republican -- like Mom and Dad -- who feels we are losing our way, please join us and stand with me.”

Republicans have responded by casting Crist as a political opportunist, and they’ve highlighted his changing policy positions and the economic decline while he was governor from 2007 to 2011. The state’s unemployment rate more than tripled to 10.9 percent from 3.5 percent during that period. It had fallen to 7 percent in August, lower than the national rate of 7.3 percent that month.

Lyman and Claudia Hussey, St. Petersburg retirees who attended the rally, said they plan to vote for Crist. They had been Republicans for 50 years and became Democrats after concluding the state and national parties had been taken over by extremists.

“We switched because the party left us,” Lyman Hussey, 73 said. “That’s what happened to Charlie.”