ORLANDO — The fabled blue wave that would have carried U.S. Sen. Bill Nelson to a fourth term failed to materialize Tuesday, ending the proudly moderate career of an old-guard Democrat, the last one standing in statewide Florida politics.

Instead the tide lifted two-term Republican Gov. Rick Scott, whose relentless ad buys and "empty suit" attacks painted Nelson as a doddering party-line voter with nothing to show for his 40 years in public office.

Scott's win, paired with Trump-endorsed Ron DeSantis' ascent to the Governor's Mansion, punctured the hopes of progressives and marked a dismal moment for the Democratic Party of this purple state.

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There was no midnight concession speech in Nelson's signature Old Florida drawl. Instead, around 12:15 a.m., longtime Nelson staffer Keith Mitchell briefly muted CNN and said just this, to a bank of TV cameras and a near-empty ballroom: "This is obviously not the result Senator Nelson's campaign has worked hard for. The senator will be making a full statement tomorrow to thank all those who rallied for his cause."

Dan McLaughlin, senior adviser to Sen. Bill Nelson, advises supporters that there are concerns on ballot counting in several south Florida counties, at the Nelson for U.S. Senate election night party, in downtown Orlando on Tuesday. (Joe Burbank/Orlando Sentinel/TNS)

As the hours passed and the temperature kept rising Tuesday evening at the Embassy Suites in downtown Orlando, an initially buoyant crowd at the Nelson headquarters grew tense. Supporters huddled tightly around two flat screens, fanning themselves with campaign signs and clutching wine glasses. They whooped for victorious local progressives while CNN blared key race alerts that shifted from thrilling to bleak for Florida's Democratic slate.

Kristy Weick, 37, a therapist from Orlando, said the night reminded her of the 2016 election. She never bought into the promise of a blue wave, she said, knowing there were many people like her parents who wanted more true moderates on the ballot.

"We just have no clue. We have no idea," she said. "The country is so divided that we don't really know what's going to happen. I can be hopeful, but hesitant."

The crowd thinned as Scott held onto a narrow but stubborn lead. Was there any chance, CNN analysts wondered, for Nelson to trigger a recount? Could some outstanding Broward County votes trapped on thumb drives hold the key?

By 10 minutes to midnight, it appeared not. In Naples, Scott claimed victory. Just a handful of straggling supporters remained in Orlando.

Republican Senate candidate Rick Scott thanks his wife Ann as he speaks to supporters at an election watch party early Wednesday in Naples. (AP Photo/Wilfredo Lee)

When hopes were still high earlier in the evening, Nelson commercials had looped on a projector screen, a montage of the senator's approachable brand of centrism. There was the familiar rocket arcing into space, black-and-white photos of a handsome Army-era Nelson, and snippets from endorsements: 'Nelson's MODERATION perfectly reflects… his state' (The Sun-Sentinel), 'STEADY, RELIABLE' (The Orlando Sentinel).

"He's from an era when people were civil to each other and worked across the aisle," said Patty Farley, president of the Democratic Women's Club of Florida, decked out in royal blue. "We've seen the results of the hatred."

Said Gary Lushine, 69, of Palm Bay: "The centrist candidates are what we need to calm things down a little bit."

Near midnight, though, as bartenders packed up the Maker's Mark and Ketel One, Gary and his wife, Peggy, left the vacant room depressed.

"We got beat," he said.

Nelson's defeat likely marks the end of a venerable career in Florida politics.

Sen. Bill Nelson passes the microphone to Andrew Gillum during a campaign rally in West Palm Beach on Nov. 3. (Scott McIntyre/The New York Times)

Over the years, Nelson, 76, has largely stayed out of the fray, his low-key folksiness part of his moderate toolkit. He has lived out his gospel of amiable bipartisanship, even as younger Democrats have embraced the unapologetic progressivism of candidates like gubernatorial hopeful Andrew Gillum, for whom the blue wave also failed to appear.

The marquee Senate race began early as Scott, 65, leveraged his personal fortune to load the airwaves with TV spots, turning Nelson into a caricature of a Washington careerist who opposes term limits.

Nelson risked a late start with Democrats fretting as his sluggish campaign failed to launch, already overshadowed by a blockbuster, highly partisan race for governor.

Nelson was grateful, he said when he finally began campaigning in earnest late this summer, that voters had a "reservoir of goodwill for me."

His first ad outlined some reliable talking points, from his service in the Army to his flight on the Space Shuttle Columbia. He went on to rail against Scott's environmental record as untold tons of rotting fish and turtles washed up on beloved beaches, casting the blame on "Red Tide Rick."

He talked up his record on immigrants, voting rights and the Everglades. He reminded voters of his bipartisan work with fellow Florida Sen. Marco Rubio after the Parkland school massacre.

He made some missteps, such as raising alarms about Russian hacking and warning Florida officials to double down on election safeguards. Scott pounced, demanding proof of the "penetration" and accused Nelson of either inventing a scandal, or disclosing classified information.

Throughout, Nelson kept a safe distance from progressive cult heroes like Bernie Sanders, quietly tending to favorite issues like limiting offshore drilling.

In an era of high-volume, highly partisan presidential rallies in airplane hangars, would voters recognize Nelson's under-the-radar accomplishments, without a signature feather in his cap?

His incremental approach to politics came in sharp contrast to Gillum, the young, black, progressive mayor who talked up a $15 minimum wage, massive raises for teachers and Medicare for all.

Nelson favored less sweeping change, talking about a $12 minimum wage and protecting the Affordable Care Act from potential repeal— "Literally the difference between life or death," he said at a recent rally in Tampa.

His moderation read as out of touch to some in this polarized time, and in many ways, Nelson was the last of a dying breed of centrist Democrats in the South.

Windemere engineer Jared West, 29, said his support for Nelson came largely from a pragmatic place.

"If Nelson doesn't win, then we have no chance of taking back the Senate and of stopping some of these really bad things from happening," he said. "In any other year, I would have supported someone who ran against him, but this is not that year."

Nelson, a fifth-generation Floridian and a lifelong athlete who grew up raising cattle in Melbourne, began his political career in 1972. He's only lost one election since then: the 1990 Democratic primary for governor.

Times files were used in this report.