WESTERVILLE, Ohio - Republicans should be worried after Troy Balderson's apparent narrow victory in Ohio's 12th Congressional District.

The reliably Republican district was anything but as Balderson eked out a victory of less than 1-percentage point over Democrat Danny O'Connor, barring any surprises with provisional ballots. Even with a Balderson victory, the result indicates tough times in the November midterms for the GOP. Talk of a "blue wave" being blunted in Ohio has been the narrative for months, but the close race may prove the Buckeye State isn't on totally solid ground for Republicans.

"It's one more piece of evidence amidst a lot of others that this is a good environment for Democrats, and it provides some opportunities to the party in the fall," said Kyle Kondik, managing editor of Sabato's Crystal Ball at the University of Virginia Center for Politics.

A year ago, many political observers thought congressional seats in Ohio were mostly out of reach for Democrats. The maps simply weren't favorable, having been gerrymandered to benefit the GOP.

Extrapolating results from a single election isn't a scientific practice, but the 12th District is exactly the kind of place Democrats need to make gains if they want any chance of picking up seats in Ohio and flipping the House in November. Suburban women - who often poll as having a strong dislike of President Donald Trump - are the key converts.

O'Connor's razor-thin loss was a relatively good sign. O'Connor had no reason to be as competitive as he did in a district that former Republican U.S. Rep. Pat Tiberi held since 2000 and hasn't elected a Democrat since 1982. Trump won the district by 11 percentage points in 2016.

However, O'Connor made inroads in some of the more suburban areas like Delaware County - just not enough to win the district.

O'Connor's results in the 12th District, coupled with positive outcomes in other special elections around the country, show the environment is ripe for Democrats, even in Ohio where many thought the "blue wave" might not reach, Kondik said.

"A lot of us who look at these races from a national perspective, we're looking for continuing trends or changing trends," he said. "This is a continuing trend in what we've seen in special elections so far."

David Niven, political science professor at the University of Cincinnati, said around Ohio, that bodes well for Democratic candidates.

Aftab Pureval in the 1st Congressional District in Cincinnati, Theresa Gasper in the 10th Congressional District in Dayton, Betsy Rader in the 14th Congressional District just outside Cleveland and even Rick Neal - who is taking on National Republican Campaign Committee Chairman Steve Stivers in Franklin County - are all facing Republicans in districts that went for Trump by less than 15 percentage points.

Niven said O'Connor's performance shows those districts could very well be in play come November.

"It speaks to an enthusiasm gap that could render an awful lot of previously unwinnable districts in play," he said.

Kondik said the rematch between O'Connor and Balderson in November could prove competitive as well, though he gave Balderson a slight edge having already won the district once.

Nationally, there are around 70 districts with about the same partisan lean as the Ohio 12th, with the majority of those in Republican hands. Democrats will now command some amount of respect given the trends of special elections since Trump's election.

They need to gain 24 seats to take back the House.

"National Democrats did not look at Ohio 12 and say this is exactly the kind of district they need to win the House back," Kondik said. "They think there are way better districts than this one."

Republicans' electoral game plan simply hasn't been working. In the 12th District, they tried talking about tax cuts to no avail. Then they switched to attacking House Democratic Leader Nancy Pelosi, but that never seemed to stick. Finally, Balderson tied himself as closely as possible to Trump, but that still made for a close race.

"They didn't do a heck of a lot to introduce Tory Balderson," Niven said. "This race, they have this kind of paint-by-numbers campaign kit which is demonize the Democrat and run against Nancy Pelosi. Why nationalize the race when the national tide is against you? It seems they stood to gain from selling Troy Balderson, and they didn't bother. This seems to be a Republican strategy they're ready to roll out wherever."

Corry Bliss, executive director of the Congressional Leadership Fund, a Republican super PAC that spent heavily in the 12th District, said in a statement congratulating Balderson that candidates nationwide need to realize what they're facing in November.

"While we won tonight, this remains a very tough political environment and moving forward, we cannot expect to win tough races when our candidate is being outraised," Bliss said in a statement. "Any Republican running for Congress getting vastly outraised by an opponent needs to start raising more money."

The loss may also point to cracks in Trump's firewall of support in Ohio - a state he won in 2016 by 8.6 percentage points. To win reelection in 2020, he must win Ohio.

The president is certainly aware of that fact. He visits the state religiously for rallies and fundraisers. He interrupted one of his golf outings at his club in New Jersey over the weekend to campaign for Balderson.

In a tweet after Balderson's apparent victory, Trump congratulated himself on helping Balderson win.

When I decided to go to Ohio for Troy Balderson, he was down in early voting 64 to 36. That was not good. After my speech on Saturday night, there was a big turn for the better. Now Troy wins a great victory during a very tough time of the year for voting. He will win BIG in Nov. — Donald J. Trump (@realDonaldTrump) August 8, 2018

But it wasn't the Trump strongholds of the district that seemed to deliver the race to the GOP. Rather, Republicans were able to triage losses in the suburbs where Gov. John Kasich - who made an 11th-hour endorsement of Balderson - runs the strongest.

"On balance, Trump probably did as much harm as good," Niven said. "This race really was about Trump, which really has to frighten the Republicans. That rendered an unlosable district into a nail-biter."

A previous version of this article listed Theresa Gasper as running in the 7th Congressional District in Dayton. It has been changed to reflect Theresa Gasper is running in the 10th Congressional District in Dayton.