The results from this week’s special election in Ohio’s 12th District are widely viewed as the latest indicator that Democrats are due for a strong performance this fall. Republican Troy Balderson still has a slim lead as of press time, but the fact that Democratic candidate Danny O’Connor garnered so much support in a heavily conservative district (he’s hovering around 49 percent of the vote) is just another sign that the GOP should be worried, experts say.

O’Connor’s solid showing in the special election comes in the wake of a stunning upset by Conor Lamb in Pennsylvania’s 18th District earlier this year. Both elections, in addition to another special election in Arizona, suggest that Democrats could continue to build on voter momentum to spur a potential “blue wave” this fall.

While Democratic odds for retaking the House seemed more uncertain earlier this summer, the party’s performance across different races since then have seemed to improve the broader outlook of this possibility. Here’s what eight experts had to say about the likelihood of a “blue wave” in November.

These responses have been lightly edited for length and clarity.

Travis Ridout, public policy professor, Washington State University

The closeness of the special election in Ohio — in a historically Republican district — suggests that Democratic voters are motivated to a much greater extent than Republican voters this year. Even millions in spending on political ads may not be enough to enthuse GOP voters this fall.

If a “blue wave” means greater-than-average Democratic participation in the midterm elections, then the chances of that happening are very high. But how many more congressional seats that nets for Democrats is still a big question. On the low end, it could be as few as a dozen. On the high end, it could be 40 seats.

Margie Omero, Democratic pollster, GBA Strategies

The results so far in OH-12 — remember thousands of ballots are still being counted — should give Republicans everywhere yet another sign of the momentum on the left. There was higher turnout than usual in suburban Franklin County. Republican groups spent millions more than did Democrats. Republicans couldn’t find something that really stuck, and so they used scattered messaging and frequent traffic changes. And, perhaps most importantly, there are 79 districts where Trump performed worse.

Democrats have had the advantage in the generic all cycle. Republicans are showing no signs of changing their fortunes. The question isn’t whether there is a wave but just how high. Will it be high enough to take back the House? The Senate? State legislative chambers around the country? In past waves, things started to break late. We’ll probably see that this year, too.

Celinda Lake, Democratic pollster, Lake Research Partners

Generally, I think the blue wave is a blue swell and we will have to work hard for it. In the final analysis the key vote may well be the turnout of millennial, young women. They are voting very democratic and very much for women candidates. I think OH-12 shows the potential.

Trump energized some of his base, and the margin was really closed by a surge of Democrats. That district is very Republican, and the blue wave there almost breached the dike.

Barry Burden, political science professor, University of Wisconsin Madison

The double-digit shift away from what Trump earned in the district is another sign that the GOP will need to play serious defense in November. Despite personal appearances by Trump and Pence, the race was basically even, a troubling sign for the party’s fortunes in the general election.

Democrats are sure to make gains in November, but it remains to be seen whether it resembles the normal amount of wins that would be expected from an out-party in a midterm election, or whether it will snowball into a thunderous victory like what Republicans delivered in 2010. There are signs, such as the high number of Republican retirements from Congress, that 2018 could be a historic wave in the Democrats’ favor.

Tim Malloy, assistant director, Quinnipiac University Poll

There’s been a sense in the past couple of months that the blue wave has been rebuilding, and it has a lot to do with the president’s behavior. A lot of these states that are tentative and at risk rise and fall with the popularity of the president.

A lot of the experts looked at Ohio as a litmus test. No matter how the White House or the GOP tries to spin it, whether the Republican wins or not, it’s not a good day. There’s every reason to believe that if it could happen in Ohio, where the president was up by 11 points, it could happen in other places.

Everybody is being urged to turn out. When you see this kind of momentum, this kind of race in Ohio, that’s the kind of thing that spurs turnout. Turnout is key and turnout will very likely be high on the Democratic side.

Spencer Kimball, communication studies professor, Emerson College

The results from this race found that Democratic voters came out at a higher percentage than normal — e.g., Franklin County, which was expected to be about 32 percent of the vote [but] was closer to 35 percent. We saw this also in PA-18. Democratic voters were more likely to vote for their nominee than the Republican voters — i.e., 91 percent of Democrats were voting for the Democrat and 82 percent of Republicans were voting for [the] Republican.

This is the opposite of what we saw in 2016, when Republicans were voting more in line with the party candidate while Democrats saw more melt from their base. Most exciting for Democrats and disturbing for Republicans are independent voters, who in OH-12 were breaking for the Democrat nearly 2 to 1.

I think a blue wave is coming in the governor and US House races, but I am not sure if it will be strong enough for Democrats to take the Senate and expect the Republicans to maintain control of the upper chamber.

Helmut Norpoth, political science professor, Stony Brook University

The Democratic near miss in the Ohio special election augurs well for the party’s prospects in November. This district has been in GOP hands for almost a century. Since 1938, a Democrat has held it for only two years, and that was in the early ’80s.

Plus, in the last congressional election, the Republican candidate won it by a margin of 130,000 votes-plus. Okay, that was a presidential year. In the last midterm year, 2014, the margin was about 90,000 votes.

To make up such enormous deficits in districts across the country could mean that Democrats might win not just the minimum 23 seats for a majority, but more like 50. A blue flood, more than just a wave.

Also remember the record number of prominent GOP House members who are retiring. Foremost is Speaker Paul Ryan. Not really a man with 30 terms-plus in the House, but one at or near his prime. To quit at that stage must mean he does not expect his party to win in November and thus for him to be speaker again. Minority leader? Nah!

Robert Erikson, political science professor, Columbia University

Past wave elections have been surprisingly strong. One reason is that seats that had previously seemed safe for incumbents suddenly became endangered. Why? In the prior election, the out-party (Dems today) had not competed strongly for a seat that they could only come close to winning but not win.

The combination of a wave of new support for the out-party plus the out-party’s renewed effort can tip the balance where incumbents had previously seemed safe enough.

With a supersize wave, bigger than observers now predict, the fallout can be enormous because gerrymandering only rearranges district lines and cannot manufacture more votes for a party. Designers of gerrymanders ignore the possibility of a 100-year flood, so their dikes are shallow. A large wave can wash away many in-party seats. I hope this analogy is clear.

But as of now, the generic polls do not show a supersize wave. The central question is more modest: Which party controls the House? The Democrats are favored but not certain of winning the most seats.

Meanwhile, if there is the wave that people think is coming, the Senate might be more in play than people think today. A strong blue wave could probably help almost all, if not all, of the vulnerable Democrat senators survive. Meanwhile, the Dems could pick up one to four seats, possibly regaining a Senate majority.