So, the Supreme Court this week OK’d sports betting by the states, giving plaintiffs Chris Christie and New Jersey a big win. Not being a gambler, I hesitate to give advice, but maybe the bookmakers can kick off their newly won legal status with the 2018 congressional elections. After all, these days, politics is somewhat akin to a professional sport, but knowing where to place a bet this fall — on the Dems or the GOP — is becoming less and less clear.

A few months ago, most political prognosticators would have characterized the Democrats’ chances of winning back the House as just shy of a sure thing. They predicted, with a modicum of certainty, an impending blue wave, destined to wipe the Republican House majority off the map. Many are still putting their chips on the Democrats to win, place and show.

But increasingly, polling numbers are beginning to show that betting the ranch on a blue wave may be a bit premature. The truth is we simply don’t know; but from a Republican point of view, that’s progress.

New surveys — private and media polls — seem to show that the enthusiasm gap, which has plagued the Republican base for the past year, might, at last, be closing. In our April 28-30 Winning the Issues survey, we asked voters to tell us how likely they are to vote in November on a 1-9 scale, with 1 meaning a voter was not planning on going to the polls and 9 meaning they absolutely would. 

Seeing red

What we found was good news for Republicans. Both parties are at parity when it comes to self-reported likelihood of voting. Conservative Republicans came in at 8.22 with Republicans overall at 8.16.

Democrats, whose enthusiasm for voting had previously topped Republicans, are now at 8.12, with liberal Democrats at 8.20.

As a Republican pollster, admittedly, you want to see this kind of result, but you also want confirmation that what you are seeing in your research is real and duplicated in other public polls. It’s a little like reproducing a result in a scientific experiment.

We now have that confirmation from two different media polls, CBS and CNN. The CBS survey (May 3-6) showed 40 percent of each of the parties’ supporters as “very enthusiastic” about voting, with 23 percent of each somewhat enthusiastic.

A new CNN survey (May 2-5) also found that Republican enthusiasm has increased in the last two months, with 44 percent now saying they are either extremely or very enthusiastic about voting. That’s up from 36 percent in March.

As the CNN poll was headlined, the “Democrats’ 2018 advantage is nearly gone.” The poll’s data showed that the movement in the generic ballot mirrored the shift in enthusiasm. The Democrats’ huge February lead of 16 points in the generic, which had slipped to 6 points in March, has now hit margin-of-error territory, with only a 3-point lead in May.

This shift is significant because the generic ballot has historically been a credible indicator of election outcomes, or at least a party’s opportunity to win. If you think about the generic ballot test as a precursor to actual election results, the threshold needed to flip the House is a minimum generic-ballot advantage of around 6 points.

Sean Trende of RealClearPolitics and Alan Abramowitz of Larry J. Sabato’s Crystal Ball put the number at 5 points. I have generally used 6 points as the predictor, based on previous election results when the House changed hands.

In 1994, Republicans won the House with a margin in the national congressional vote of 6.8 percent. In 2006, Democrats won it back with a margin of 8 percent. In 2010, it flipped again with Republicans winning by a margin of 6.8 percent.

In 16 of the 18 midterm elections that have occurred since World War II, the party holding the White House has lost seats, though the number has varied widely. As of Tuesday, the RealClearPolitics generic ballot average showed a 5.2 advantage for Democrats — definitely in the ballpark to flip the House — but like the enthusiasm gap, the trend line is encouraging for Republicans.

While recent polls clearly offer some better news for the GOP, turnout in primaries in places like Ohio, Indiana and Pennsylvania have been mixed in terms of assessing partisan voter enthusiasm. So many variables affect turnout: the quality of the candidates and their campaigns; whether the primary is hotly contested and therefore probably very negative; and the temperature of the national political environment.

What’s the message?

Over the past two months, Democrats have scrambled to find a message that works. They’ve road-tested Russia, impeachment, Stormy Daniels and tax cuts. They’ve tried to transform themselves into deficit hawks and twist their outdated Keynesian fiscal policies into “mainstream” economics. But clearly, voters aren’t buying what they’re selling just yet, a fact not lost on national Democrats.

Talking about the elections last week, House Minority Leader Nancy Pelosi admitted, “It comes down to an economic message. … The financial instability of America’s families is something that needs to be addressed. … The winning message is our economic agenda.”

Their problem is that no one knows what that economic agenda is, besides opposing tax cuts, generally not a good strategic position to be in just months away from a national election. Ask Walter Mondale how a promise to increase taxes worked out for him and his party in 1984.

The CBS survey asked voters whether Democrats have explained what they would do if they won Congress. Seventy-two percent said no; even 69 percent of Democrats agreed with that. If Democrats don’t know what they would do with congressional control, they can’t expect the voters to know either.

What these latest polls may be telling us is that the vaunted blue wave may have peaked too soon, run aground on the realities of a growing economy. But five months is a lifetime in politics.

For the past year, the inside-the-Beltway crowd, Democrats and many Republicans, have operated on the assumption that Republicans were headed for a big 2018 defeat. There are still a lot of “ifs” that may determine who claims the Congress in November, but with the generic ballot hovering at +5 for Democrats, at this point, the outcome of the November election is no longer clear.

Watch: Which House Races Are the Parties Targeting? Look to the Money, the TV Ad Money

David Winston is the president of The Winston Group and a longtime adviser to congressional Republicans. He previously served as the director of planning for House Speaker Newt Gingrich. He advises Fortune 100 companies, foundations, and nonprofit organizations on strategic planning and public policy issues, and is an election analyst for CBS News.