The BBC correspondent in Washington says even if the Democrats lose the seat, they can claim a moral victory in OH, and will point to the results as further evidence that they are poised for success in November.
The candidates were locked in a razor-thin race, which they will reprise in the general election in just three months. Mr. Husted added there are 3,435 provisional ballots and 5,048 absentee ballots outstanding.
The Associated Press does not declare winners in races subject to an automatic recount.
A Republican clung to a narrow lead in a hotly contested U.S. House of Representatives race in OH late on Tuesday, holding off a strong challenge in the reliably Republican district after a late show of support from President Donald Trump.
The race matched consistent trends in special elections and statewide contests since Trump took office: Turnout sagged in rural, heavily Republican areas; surged in suburban areas; and swung in Democrats' favor in those suburbs when compared to the 2016 election results.
The results would help determine the political landscape - and Trump's standing within his own party - as the GOP defends its House and Senate majorities this fall.
Kobach, the Kansas secretary of state, built a national reputation as a conservative agitator for both tough immigration policies and strict voter identification laws.
In Kansas, Republicans were fighting among themselves in an unusual battle for governor in which the president sided with the incumbent's challenger.
Ohio Govenor John Kasich, a leading voice in the GOP's shrinking anti-Trump wing, once represented the district in Congress.
Regardless, while Republicans were spared from headlines proclaiming another stunning Democratic win, it's a bad sign for the GOP that provisional ballots are even entering the discussion in a district Donald Trump won by 11 points in 2016.
"It's Ohio's 12th district, and he's going to hopefully be here a long time". Kobach told reporters that the endorsement "came just in time" and that he expected it to help him, as it has helped other candidates in other races. "The Republicans are embarrassed by their president, and because of that I think they want to put a brake on him, to send a message to him that his filthy talk, his boorish behavior, the way they've treated those little children down there on the border, his racism, is against OH values".
O'Connor and his Democratic allies railed against the tax plan, casting it as a giveaway for the rich that exacerbates federal deficits and threatens Medicare and Social Security.
"When you look at the economy since he began, I'd say we're moving in the right direction and need more Republicans in there to support his agenda", he said.
Democratic women could outnumber white male colleagues in the House after November, a recent study suggested. "It's a huge election", said Doug Marmie, Newark City councilman, at Mr. Balderson's Newark celebration.
With dozens of Republican lawmakers retiring this year, the minority party has a decent chance of taking over the House.
The field was set in two Senate contests as well. "He will win BIG in Nov". "Congratulations to a future STAR of the Republican Party, future Senator John James", Trump tweeted.