Democrats won a special election to fill a vacant Kentucky state Senate seat this week, flipping a district Republicans held for decades and signaling that the suburban shift that helped create a blue wave in 2018s midterm elections may continue in 2020.

Dr. Karen Berg defeated Republican candidate Bill Ferko by 14 points to win the race to replace longtime GOP state Sen. Ernie Harris, who retired in April after holding the seat in suburban Louisville for 25 years. Berg narrowly lost to Harris in the 2018 general election, but will now hold the seat until that term expires in 2022. The win marked the first time Kentucky Democrats have flipped a state Senate seat since 2010.

Bergs victory, which was announced Tuesday after officials finished counting absentee ballots in the June 23 election, will barely dent Republicans grip on the Kentucky state Senate, where the GOP still holds a supermajority. But it is the latest sign of trouble for the GOP in the suburbs of Kentuckys largest city and may foreshadow further problems for the party in November as its suburban base continues to erode under President Donald Trump.

Nationwide, the Republicans are in great danger of losing the upper-status professionals who used to side with them, said Stephen Voss, a University of Kentucky political scientist who specializes in voter behavior and election patterns. If that realignment in those voters becomes permanent, then the Republican Party is in trouble.

Democratic gains in the suburbs of Louisville, Lexington and Cincinnati have already helped the party maintain a foothold in the Bluegrass State, where suburban swings powered Gov. Andy Beshears (D) victory over former GOP Gov. Matt Bevin a year ago. Nationwide, rapid shifts in the suburban electorate helped Democrats win back majority control of Congress and cut into Republican state legislative majorities in 2018, especially as the party turned to first-time candidates like Berg to win over areas that have long favored the GOP.

Berg was drafted into the 2018 race by Emerge Kentucky, a chapter of a national organization that recruits and trains women to run for office. The group has helped elect three dozen women in Kentucky, including seven state legislators who won races in 2018 and Lt. Gov. Jacqueline Coleman, a former teacher who ran alongside Beshear last year .

The suburbs have become an ever-larger source of success for Democrats, especially as women have abandoned the GOP during the Trump years. Hillary Clinton carried the inner suburbs of cities nationwide in 2016, even as Trumps success in rural areas pushed him to victory. In 2018, 38 of the 41 seats Democrats flipped on their way to the House majority were in suburban districts . The party won in places like Orange County, California, and central Oklahoma, where Rep. Kendra Horn shocked observers by winning a House seat the GOP had held for 44 years.

Suburban victories have also powered Democrats at the state legislative level, where they picked up 300 seats in 2018 and last year won control of the Virginia state legislature for the first time in more than two decades.

That success and Bergs close loss two years ago helped turn Harris seat into a Democratic target once the veteran lawmaker retired in April. Berg focused her campaign on her experience as a physician and professor at the University of Louisvilles school of medicine, arguing that healthcare is a right and that Kentucky needed to make investments to improve public education, two issues that have taken center stage in recent Kentucky elections.

The Democratic Legislative Campaign Committee, the party arm that focuses on statehouse elections, spotlighted Bergs race as a key early contest in its aggressive push to build on 2018s wins. Democrats across the board have also identified suburban areas as key to their 2020 hopes , particularly as the party tries to expand its House majority, win back the U.S. Senate and flip state assemblies in Texas, Arizona, Pennsylvania and other key states before redistricting begins.

Berg was likely helped by record turnout among Kentucky Democrats, thanks to expanded mail-in voting amid the coronavirus pandemic and a contested Democratic primary in the race to face GOP Senate Majority Leader Mitch McConnell this fall. The special election took place alongside the primary, which was delayed more than a month due to the pandemic. Results were announced Tuesday after election officials took a week to count and certify absentee ballots, which made up more than three-quarters of the votes cast in Kentucky last week.

Bergs victory excited Democratic leaders looking for signs that Beshears suburban gains in 2019 werent an aberration but the beginnings of a real and potentially lasting shift.

It shows that good candidates with the right resources who arent afraid to campaign on health care and public education can win in these suburban areas that have traditionally been Republican, even in Kentucky, state Senate Minority Leader Morgan McGarvey told HuffPost on Tuesday.

Democrats have a long road back to the majority in Kentucky, where the GOP still holds a 28-10 advantage in the state Senate and a 24-seat grip on the state House. But Bergs victory will give the party at least a temporary boost in a state where it is trying to rebuild after losing total control of the legislature for the first time in a century four years ago.

And yet another win in a district like this one, especially in a supposedly deep-red state like Kentucky, will only further bolster Democrats belief that they can score even bigger victories in suburbs nationwide later this year.

The unhappiness seen among affluent professionals with the Republican Party has stuck around now for a couple of years, Voss said. If it continues on to November, then prospects for the Democrats in terms of the Senate and the presidency are looking very good.