As goes Jeffco, so goes Colorado.

That adage about suburban Jefferson County’s bellwether status has been mostly true for decades, and that’s why what happened on Election Day has some state Republican stalwarts sounding the alarm.

No one who follows politics in Colorado needs to be reminded that the GOP got its clock cleaned by state voters this year by a Democratic sweep nearly without precedent.

According to the Colorado Department of Public Health and Environment’s statistician, there aren’t more than around 50,000 state residents – roughly the population of Broomfield – who were alive the last time Democrats controlled the levers of power the party is poised to wield in the wake of the election, holding every statewide constitutional office and majorities in both chambers of the General Assembly.

Bolstered by record turnout among the state’s surging ranks of unaffiliated voters, who leaned left by a wide margin, Democrats elected a governor, lieutenant governor, secretary of state, treasurer and attorney general.

They also swept every one of the battleground state Senate races by double digits, handing them the gavel, and increased the party’s majority in the state House, including a win in a Jefferson County seat that has never before elected a Democrat.

But while things looked bad for Republicans the morning after the election, it’s only after officials finished counting the votes – in nearly every case shifting the margins further toward the Democrats – that the extent of the wipe-out has become clear.

Look no further than Jefferson County – encompassing suburbs and foothills west of the metro area, it’s the state’s fourth-most populous county, behind Denver, El Paso and Arapahoe – to see that the breadth of the GOP’s defeat is matched by its depth.

Jeffco, once as solidly Republican as any county in the state, has been trending blue for more than a decade, its voters favoring Democrats at the top of the ticket – for president, governor and the U.S. Senate – in every election since 2006, but it’s still been considered a swing county and has reliably produced GOP lawmakers and county officials.

But that can’t be said after this month’s election.

Out of the dozen legislative seats that represent Jeffco residents, just one is held by a Republican – state Rep. Colin Larson, a newcomer who won the nomination in the state’s closest legislative primary in June – while all three of the congressional seats that include parts of the county are held by Democrats.

Perhaps even more stunning, Jeffco voters elected only one Republican at the county level – and Sheriff Jeff Schrader, who won a second term, didn’t have a Democratic opponent.

With the election of Lesley Dahlkemper as county commissioner – she defeated a Republican who was appointed to the office last year – Democrats will hold a majority on the three-member county commission for the first time since the mid-1990s, when Betty Miller and Gary Laura each served a single term. (The last Democratic majority before that was the mid-1950s, when two commissioners named Emil Schneider and Walter True were on the board.)

Jeffco has elected Democrats to county office over the years – a county commissioner here, a clerk and recorder there – but they’ve been relatively rare and haven’t lasted long. This time, however, the party nearly ran the table, winning the offices of treasurer, assessor, coroner, and ousting the incumbent clerk and recorder.

Even the Republican county surveyor, an office not traditionally viewed through a partisan lens, was turned out by Jeffco voters

“I think it really shows that these unaffiliated voters were voting a straight, anti-Trump ticket,” Dick Wadhams, a Jeffco resident and former state Republican Party chairman, told Trail Mix. “It made no difference who the Republican was in what race at what level. They were voting against Republicans.”

It wasn’t too long ago that the county was represented by two Republicans in Congress and sent mostly Republicans to the Legislature, recalled Wadhams, who ran a string of winning statewide campaigns for governor and senator.

“Jeffco used to be a Republican bulwark, going back to the ’60s and ’70s and into the ’80s and ’90s. The courthouse was solidly Republican for decades,” he said. “It just shows you the depth of the Democratic victory.”

That’s the starting point for the sobering pep talk he’s been delivering to GOP groups since the election – that Republicans had better draw the right lessons from this year’s loss or risk going the way of the dinosaurs whose footprints adorn a Jefferson County landmark not far from his home.

“We lost the governor’s race and all those things below it because there is an anti-Trump fervor that swept through Colorado,” Wadhams said, adding that his conclusion echoed the findings of a survey of unaffiliated voters conducted after the election by GOP firm Magellan Strategies.

“I am not an anti-Trumper,” Wadhams said, noting that he heartily approves of the president’s accomplishments even as he frowns at his tone. “But I think we have to acknowledge reality.”

Where does that leave Republicans who aren’t willing to throw in the towel?

Wadhams’ message is simple: “The only thing that matters is the reelection of Cory Gardner,” the Republican senator whose term is up in two years.

“Cory is the last Republican bastion in the state,” Wadhams said. “And if we don’t start nominating candidates like Cory Gardner who can articulate a positive agenda. He’s dynamic, he’s young, he’s thoughtful and articulate – exactly the kind of Republican we need to have to attract these unaffiliated voters.”

For Republicans who aren’t enthused about Gardner – he has his detractors in the GOP, including those who say he isn’t conservative enough – Wadhams said they need only look to the results this year in Jefferson County for a glimpse of what the state’s future might look like without him.

CORRECTION: Democrats last held two seats on the three-member Jefferson County Board of Commissioners in the mid-1990s, not the mid-1950s, as this column originally said.