Republicans are in panic mode about the prospect of losing a special election Tuesday in a Republican-leaning congressional district in Ohio.

But how much should Democrats be celebrating? It's not a given that their candidate, Democrat Danny O'Connor, will win this open seat vacated by longtime Republican congressman Patrick J. Tiberi. But O'Connor has been giving Republican Troy Balderson a run for his money, with a key poll showing the race basically a dead heat.

Some Democrats and independent analysts think just getting this far is a strong signal that Democrats are well positioned to take back control of the House of Representatives in November for the first time in eight years.

No matter the results, writes Navin Nayak, executive director of the Center for American Progress Action Fund in a memo, “it will only serve as a reminder of how difficult the political climate is for Republicans heading into November.”

Republicans counter that Democrats need to win to actually prove they can win.

Here's a look at some of the key measures to determine whether the mere fact that this race is competitive should give Democrats even more confidence that they are likely to take back the House.

This is and isn't the kind of seat Democrats need to win to take back the House: On paper, the Ohio 12th District, which frames the outer Columbus suburbs, is not one that Democrats need to concentrate on in their battle to take back the House. They need to pick up a total of 23 seats (after factoring in any of the seats they lose) to get the bare majority. The nonpartisan election analysis blog Cook Political Report calculates that there are 60 GOP districts that are more Democratic than this one.

House Democrats see a clear trend: They are overperforming deep in Republican territory, so why shouldn't they be confident they can win swingier districts such as the 23 Hillary Clinton won that Republicans hold?

But when you set aside the math and the map, you could argue this is also a district that Democrats should be winning to get back control of Washington.

It's full of higher-educated, mostly white suburban voters who lean Republican. They supported Donald Trump in 2016, but the president's meh approval rating in the district now (under 50 percent) suggests that support was offered somewhat reluctantly. To state the obvious, these are exactly the kind of voters Democrats need to win over, not just to take back the House in 2018 but to take back the White House in 2020.

Democrats are just more motivated than Republicans right now to be active in politics: This is something both sides can agree on. Republicans who allow that they might lose argue that it's not because the district likes the Democrat better, but because GOP voters just aren't going to vote.

“You all know, it’s a tight race,” Balderson told supporters Friday, Politico reported. “And everybody wants to know, why is it tight? Why is it tight? Because this race is all about turnout.”

To some degree, they're right. This race is all about turning out either side's base in the depths of summer vacation season. But blaming a near-loss or full loss on turnout entirely ignores one reality: Even if all the Democratic voters turned out in this district, it wouldn't be enough to elect O'Connor. Registered Republicans outnumber Democrats 2 to 1.

If O'Connor wins or comes close to winning, it's probably because he's converted some Republican-leaning voters. That would go a long way to helping Democrats feel more confident that they can take back the House, since they'll need to win over those voters in states such as Florida, California and Minnesota in November.

This race is all about Trump: Presidents always cast a large shadow in the first congressional election of their tenure. But Trump so completely dominates the political conversation — he even goes out of his way at rallies such as the one he held Saturday in Ohio to make it about himself — that it's fair to say this race is a referendum on Trump.

By that measure, the fact that this race is competitive at all raises a troubling question for Republicans: If voters who elected Trump by 11 points are hesitant to send a candidate whom Trump endorsed to Congress, what does that say about how these voters feel about Trump now? Expand that apparent skepticism of Trump to a dozen or more Republican-leaning districts across the country in November, and Republicans could be in trouble. Especially in a midterm election that seems as nationalized as this one is shaping up to be.

We've already had glimpses of Trump's unpopularity a year and a half into his tenure. Democrat Conor Lamb won a district Trump won by 20 points in 2016. Democrats have flipped more than 40 state legislative seats, including some deep in Trump country in Oklahoma and Kentucky. This race will complete the picture, said Stu Rothenberg, a nonpartisan political analyst who writes the Rothenberg Political Report, in an email to The Fix. 

“The closeness of this contest reflects Trump's weakness, and this special will show us how serious those problems are,” Rothenberg wrote. “To me, a tight race with Balderson winning by a few points would confirm the coming Democratic wave.”