A win is a win is a win. Unless it's the sort of win Republicans looked like they might eke out on Tuesday night in Ohio. The race remained too close to call Wednesday, with more than 99 per cent of votes tallied.

One way or another, political analysts say, the potentially devastating news for Republicans is this: The solidly red 12th congressional district is no longer dependable for the Grand Old Party, and neither are their chances of holding the House of Representatives in the fall midterm elections.

The squeaker outcome between Democrat Danny O'Connor and Republican candidate Troy Balderson could strengthen Democrats' resolve that they're on the verge of a "blue wave" to win a tsunami of seats and flip the lower chamber. It could also spell trouble when it comes to how closely the Republican party's candidates can afford to align themselves with U.S. President Donald Trump.

Balderson stands near a polling station Tuesday. The special election is the last competitive race before midterms in November. (Shannon Stapleton/Reuters)

"At one level, the Democrats have already won," Ohio State University politics professor Herb Asher said. "They've sent their message. It becomes an indicator that November may be a happier time for the Democrats."

Balderson was leading O'Connor for a House seat in the special election by 1,700 votes Wednesday morning. Officials said a final result would only be announced after counting more than 8,000 provisional and absentee ballots.

The margin of victory is tiny enough, analysts say, to send Republicans into a panic over whether they'll lose the House come November, even as Asher predicted Republicans would spin the outcome positively.

"This is closer than it should be, but listen — a win is still a win," said Ryan Stubenrauch, an Ohio-based Republican strategist who lives in Delaware County in the 12th district.

As for the suggestion that Democrats, despite likely losing this special election, still have reason to celebrate, Stubenrauch wasn't so sure about that.

"There's no such thing as moral victories in politics."

But what's telling is how close the race was, given that the state's Republican governor, John Kasich, last weekend told ABC News it shouldn't have even been a toss-up. Pundits had said anything less than a seven-point win for Balderson would be an embarrassment.

"It really doesn't bode well for the Republican party because [the 12th district race] shouldn't really be contested," Kasich told ABC, adding that Trump's "chaos" presidency was unnerving Ohioans.

Democratic candidate Danny O'Connor with his fiancée, Spenser Stafford arriving to vote at the Noor Islamic Cultural Center on Tuesday in Dublin, Ohio. Stafford, a registered Republican, was crossing party lines to vote for O'Connor. (John Minchillo/Associated Press)

His remarks were prescient.​

Balderson's likely single-point win "would still be a big under-performance of the president who won it by 11," noted Geoffrey Skelley, with the University of Virginia's Center for Politics.

"Republicans dodged a bullet tonight, but they have to find a way to match the Democrats' voter intensity going forward if they want to hold the House," Republican strategist Ford O'Connell wrote in an email.

"Some Republicans candidates might want to hold President Trump at arm's length, but running away from the president entirely is a fool's errand."

Even so, some skeptical Republicans may begin to view the much-hyped blue wave as very real. A victory for Democrats in the election in central Ohio would have provided compelling evidence, but a narrow loss like this is nothing to sniff at.

"That's what everybody was trying to figure out. Is this blue wave election going to happen in November?" Stubenrauch said.

High voter turnout, fuelled by Democratic enthusiasm, likely helped O'Connor pull ahead. But bringing in Trump, whose approval rating stands at just 46 per cent in the district, was a calculated risk.

Ohio Gov. John Kasich said the race in the 12th district didn't bode well for the Republican Party. (Aaron Josefczyk/Reuters)

"The calculation was: What is going to get the base to turn out for an August congressional election — the president being quiet, or doubling down?" Stubenrauch said. For Democrats, he said, "this was an opportunity for some people in more liberal districts to stick your thumb in president Trump's eye."

Balderson's wafer-thin victory might also suggest Trump's polarizing leadership can attract enough of a base to win elections. But Trump can also be a liability, making off-message statements that may distract from local issues.

Last weekend, as the president stumped for Balderson in Ohio, he chose hours before his rally to tweet insults at one of Ohio's favourite sons, NBA luminary LeBron James.

Balderson has called himself a "Trump guy" and received the president's endorsement, but he hasn't directly addressed the claim that he didn't invite the president to the rally over the weekend, sidestepping the question to say only that he was "honoured" the president came.

"There was talk of: Will Trump's visit be a net positive?" Asher said. "Will it get the Republican energized to come out and vote? Or will it be a negative because it will energize Democrats and offend a large number of independents?"

Trump, he said, has proven to be a "mixed blessing" for the party.

"Trump will claim he put Balderson over the top. Balderson will probably claim that, too, just to be a good loyal Republican," Asher said. "But tonight does suggest the Trump brand — and the Republican brand, for that matter, as defined by Trump — is not as popular in districts like this."

The president later did indeed tweet that Balderson owed his victory to a Trump bump.

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. —@realDonaldTrump

Unlike in 2016, when voters gave Trump a comfortable lead, this time they seemed to be communicating "buyer's remorse," said Democratic strategist Hank Sheinkopf.

"If [Balderson] can lose in Ohio, it's a clear indication Trump is bad news for the Republicans in congressional races in the heartland," he said. "They won't want him around because they don't want to lose their seats."

Trump's practice of using polarization and "fear" to send Republicans to the polls was also being tested, Stubenrauch said. Trump and Republican groups have offered dark visions of violent immigrants and the restriction of the right to bear arms, while drawing links between O'Connor and Democratic House Minority Leader Nancy Pelosi.

"In the 12th district, you've got a bogeyman in Nancy Pelosi," Stubenrauch said. "And fear is a motivator. They were saying, 'They're gonna take your guns away or targeting pro-life…or talking about sanctuary cities.'"

...Danny O’Connor is a total puppet for Nancy Pelosi and Maxine Waters – Danny wants to raise your taxes, open your borders, and take away your 2nd Amendment. Vote for Troy on Tuesday! —@realDonaldTrump

The payoff, he said, was for conservatives to go stampeding to the polls to prevent a far-left takeover of Congress.

It may have worked to an extent, but Democrats now get to seize momentum in the last competitive race before the midterms, despite losing. By most counts (when vacancies are factored in), they need to flip 23 seats to regain the lower chamber, a goal that was already in range before Tuesday. Their narrow loss in Ohio could give Democrats reason to believe that other solidly red districts might also be in play.

Tuesday's outcome could still drum up Democratic funding for other races, for example, and it might also put into play other suburban midwest battlegrounds like Iowa, Wisconsin, Michigan and western Pennsylvania.

"This would say to the Democrats, you might be able to expand the playing field in November," Asher said. "That would be a lesson here."