With the specters of Pennsylvania and Arizona and Alabama haunting their dreams, Republicans have a new special election to worry about: Ohio’s 12th Congressional District.

Rep. Pat Tiberi announced last year that he would step down early from this district, which covers the areas north and east of Columbus. But Republicans are locked in a bitter primary over who should bear the party’s standard to replace Tiberi, with establishment Republicans entrenched on one side and the archconservative House Freedom Caucus on the other.

Whoever emerges in the May 8 primary is likely looking at a more difficult race than one might otherwise expect in this district, which Tiberi had held since 2002 and carried with two-thirds of the vote in 2016. The Cook Political Report places the district as R+7 and rates the race as a toss-up.

Republicans in the state say that already shaky outlook could darken even more if conservative insurgent Melanie Leneghan prevails over Tiberi’s chosen successor, state Sen. Troy Balderson, in the primary on Tuesday. I asked an Ohio Republican with ties to the state GOP establishment to rate, on a scale of 1 to 10, how worried the GOP should be.

“Depends on who we nominate — 10 if it’s the wrong candidate, 7 if it’s one of the good ones,” this person told me. “Either way, the Democrats are coming, and this is a seat they can flip.”

The Ohio 12th is not quite the same as the Pennsylvania 18th — this is not an area with a working-class Democratic history that has only recently turned red. It has had a Republican representative, with a brief two-year exception, since 1939.

But this is also a well-educated and suburban constituency, the kind that might be blanching at President Trump and the sort of voters who would be crucial to Democratic dreams of retaking the House. We have mounting evidence that Democrats can compete in redder districts than previously thought possible. The Ohio 12th special election on August 7 will be the next test.

But first, the May 8 primary — which already sees Republicans courting disaster.

The Ohio 12th Republican primary: Troy Balderson versus Melanie Leneghan, explained

There are at least four viable Republicans in the GOP primary for the special election, though Balderson and Leneghan have come to personify the establishment versus insurgent conservative dynamic. Balderson has been in the Ohio Senate since 2011, while Leneghan is an area businesswoman and a local government official.

On Balderson’s side is Tiberi himself, who has spent $150,000 on a TV ad promoting his chosen successor, as well as several elected county officials from the district and former state Republican chairs. The former Congress member has sounded the siren, citing Conor Lamb’s win in the Pennsylvania 18th election as evidence of what could happen if the GOP nominates too conservative a candidate.

“We just saw last month in Western Pennsylvania a seat that Donald Trump won by twice as many votes go to a Democrat because the Republican was too conservative for the district,” Tiberi told the Columbus Dispatch.

Not that Balderson is portraying himself as a centrist. His marquee campaign ad touts his bona fides as a spending hawk who wants to build Trump’s wall on the Mexican border while defending Christian values.

Nevertheless, archconservatives in Ohio and Washington are throwing their weight behind Leneghan over Balderson. Ohio Rep. Jim Jordan, founder of the House Freedom Caucus, has backed her, as has the Freedom Caucus as a whole. As Politico reported this week, Club for Growth is buying television time for a new spot slamming Balderson for being insufficiently opposed to Obamacare.

Leneghan, meanwhile, is touting herself as “a Christian conservative, a constitutional conservative, a Trump conservative.”

Politico summarized the dynamic nicely: National Republicans fear Leneghan’s far-right campaign would alienate the more moderately minded district, which elected Tiberi or John Kasich, now governor, to the House for the past 35 years, while Jordan and the Freedom Caucus argue that Republicans need to energize the conservative base if they are going to match the Democratic enthusiasm in 2018:

Another national Republican strategist put the situation in Ohio even more bluntly: “If she wins, the seat’s probably gone.” Jordan dismissed that possibility in an interview with POLITICO, saying, “That’s always what the establishment and the swamp says. “You’ve got to turn out the grassroots, if you’re going to win a special. So she’s the best one equipped to do that. She’s the best equipped to win the general,” Jordan said.

The one poll we have shows a free-for-all: Balderson at 17 percent, Leneghan at 11 percent, veteran Air Force officer Tim Kane at 10 percent, and state Sen. Kevin Bacon at 10 percent. Kane in particular is getting a big boost from an outside super PAC that promotes veterans running for office, which is spending six figures on a TV spot backing him.

The fear among establishment Republicans is that Kane and Bacon will help split the more mainstream GOP vote, leaving an opening for Leneghan. We’ll find out on Tuesday.

How Democrats could win on August 7

The Democratic primary isn’t nearly as dramatic. Democrats think they have a few viable candidates: Danny O’Connor, the Franklin County recorder who has the endorsement of former Gov. Ted Strickland and Rep. Tim Ryan (D-OH) and is raising the most money; Zach Scott, a former Franklin County sheriff with strong name recognition; and John Russell, a local farmer with ties to area progressive grassroots groups.

O’Connor would appear to be the favorite, by virtue of his endorsements and fundraising. But the Democratic odds might be founded less on which candidate emerges from the May 8 primary and more on whether a district that has been sending Republicans to Congress for almost all of the past century can bring itself to vote for the other party.

The climb is significant for Democrats: Part of the district covers Franklin County, home of Columbus, but it also extends into Licking, Morrow, and Delaware counties — which never, ever vote for Democrats.

“None of them have voted Democratic for president since at least 1964, and Delaware hasn’t voted Democratic since 1916, the longest Republican-voting streak of any county in Ohio,” Kyle Kondik at the University of Virginia’s Center for Politics, who wrote a book on the state’s politics, noted last month.

But he also noted that Delaware County (and much of the district) is better educated and wealthier than the nation as a whole — and those highly educated white voters tend to be the most skeptical of Trump. From Kondik:

That said, Delaware is also the most affluent and educated county in Ohio, and it’s also the fastest-growing. It’s also one of only four (of 88 total) counties in Ohio where Donald Trump actually performed worse than Mitt Romney (to put that in context, Trump improved 11 points on Romney’s statewide margin in Ohio, turning a three-point loss into an eight-point win in a traditional bellwether state).

Updating his prognosis this week, Kondik was much more bullish on the Democratic chances of taking the Ohio 12th, pointing to their strong showing in the Arizona special election earlier this month.

“In our mid-March update, we questioned the ability of Democrats to truly compete for this seat because of its longstanding Republican lineage, but a strong Democratic showing in AZ-8’s recent special — the Democrat lost by less than five points in a solidly Republican district that Trump carried by 21 points — is an indicator that OH-12 should be an extremely competitive race,” he wrote.

This all helps to explain why Democrats believe a Leneghan candidacy on the Republican side gives them the best shot — this is a district that might already be skeptical of Trump and its independents and more moderate Republicans might be willing to back a Democrat if the alternative is an archconservative hugging Trump as tightly as she can.

It should be a competitive August election and, given how those have gone for Republicans lately, it could be the next harbinger of a 2018 Democratic wave.