With an 8-point lead on the generic congressional ballot — among their highest of the cycle — Democrats could well be on the cusp of a major wave election.

We say this based on historical trends and the current political mood. At this point in 2018, the last blue wave, Democrats led the generic ballot by roughly 7 points before gaining 41 House seats.

Moreover, the president’s party losing seats in midterms is essentially law in American politics: It has happened in all but three elections since the Roosevelt administration.

FOX NEWS POWER RANKINGS: FOR THE DEMOCRATS, WHERE COULD IT POSSIBLY GO WRONG?

From 1934 through 2018, the president’s party lost an average of 28 House seats and four Senate seats, and over the past five midterms, the average net loss for the president’s party has been 31 House seats.

To be clear, Republicans could make up ground for a number of critical reasons: Democrats remain divided ideologically, lack a message and an identity other than being anti-President Trump, and Republicans have a considerable cash advantage.

DEMOCRATS SEE NEW CHANCES TO FLIP RED STATES — BUT A $400M GOP SPENDING ADVANTAGE COULD DERAIL THEIR PLANS

That being said, by most measures, Democrats have the upper hand in the House and a genuine opportunity in the Senate.

Recent polling suggests Democratic strength in several key Senate battlegrounds — enough to put the upper chamber in play in what was supposed to be a GOP-friendly map.

DEMOCRATS ARE WITHIN STRIKING DISTANCE IN THE SENATE, BUT SHOULDN’T CELEBRATE YET

In North Carolina, Democrat Roy Cooper leads Republican Michael Whatley by nearly 10 points in the polling average.

In Michigan, Democrat Abdul El-Sayed holds a narrow 3-point lead over Republican Mike Rogers, who had led during the spring and part of the summer as Republicans emphasized El-Sayed’s socialist lean, controversial statements, and his association with far-left influencer Hasan Piker.

EL-SAYED’S SCATHING OBAMA CRITIQUE RESURFACES AHEAD OF JOINT CAMPAIGN RALLY

In Maine, Democratic challenger Troy Jackson holds a slight edge over Republican Sen. Susan Collins, although the race remains effectively a toss-up per RealClearPolitics.

Victories in those three states alone would not give Democrats control of the Senate. They need a net gain of four seats.

SCHUMER WARNS OF REPUBLICAN ADVANTAGE THAT COULD CHANGE THE BATTLE FOR SENATE CONTROL

The deeper problem for Republicans is that Democrats have expanded the map.

In Texas, which has not elected a Democrat statewide since 1994, James Talarico leads Republican Attorney General Ken Paxton — President Trump’s preferred candidate — by roughly 3 points.

FOX NEWS POLL: IT’S A LONE STAR SENATE SHOWDOWN BETWEEN TALARICO AND PAXTON

Races in other reliably Republican states, including Iowa, South Carolina, Alaska, and even Kansas — which has not elected a Democratic senator in nine decades — also show Democratic candidates running far more competitively than expected.

The Democratic Party’s weak brand — exacerbated by the growing influence of socialists and the far left — could alienate moderate voters, an argument Republicans are now making. Further, with an average approval rating of 40%, the Democratic Party is virtually as unpopular as President Trump.

Most of these polls remain within the margin of error. But that should offer Republicans little comfort: The fact that these races are close at all reflects a national environment currently favoring Democrats.

That is not to predict that Democrats will win all, or even most, of these contests.

SLEEPER SENATE RACE EMERGES AS UNEXPECTED HEADACHE FOR REPUBLICANS AHEAD OF MIDTERMS

Outside North Carolina, their leads are essentially ties, and polling has underestimated Republican support in several recent elections.

The generic ballot also cannot be applied mechanically to an individual Senate race or House district, particularly when the number of competitive districts has declined sharply since 2018.

The Cook Political Report currently rates 21 House races as toss-ups and another 21 as leaning toward one party or the other. In 2018, 75 races were considered competitive — a decline driven by redistricting and growing political polarization.

Even with those caveats, Democratic competitiveness in traditionally Republican territory is significant in its own right.

DEMOCRATS THINK A BLUE WAVE IS BUILDING. HERE ARE 3 FORCES THAT COULD STOP IT

It reflects voters’ deep frustration with the state of the economy. In Fox News polling, nearly four times as many Americans said they were falling behind financially as said they were getting ahead, 44% to 12%.

Fox also found that 55% believed Democrats would do a better job handling inflation, compared with 40% who chose Republicans. 

President Trump’s approval rating, meanwhile, is below 40% — another warning sign.

Low presidential approval has often produced punishing midterms. In 2010, when President Barack Obama’s approval stood at a still-weak 44%, Democrats lost 63 House seats and six Senate seats.

CLICK HERE FOR MORE FOX NEWS OPINION

Nevertheless, Republicans retain important advantages.

They have only just begun deploying their substantial cash advantage. The Democratic Party’s weak brand — exacerbated by the growing influence of socialists and the far left — could alienate moderate voters, an argument Republicans are now making.

Further, with an average approval rating of 40%, the Democratic Party is virtually as unpopular as Trump.

It is also possible that lower-propensity Republican voters heed Trump’s call to behave as if he were on the ballot and turn out. If they do, the election results could look markedly different from today’s polling.

Ultimately, both history and current data favor Democrats. They are likely to win the House and have a better-than-even chance of capturing the Senate. They are competitive in states that would ordinarily be out of reach and are running strongly across the core battlegrounds.

CLICK HERE TO DOWNLOAD THE FOX NEWS APP

But with three weeks remaining, a Democratic sweep is far from a foregone conclusion. Republicans still have structural advantages and Trump’s unparalleled ability to mobilize his base.

The direction of the race is clear; the scale of the outcome is not.

CLICK HERE TO READ MORE FROM DOUG SCHOEN

CLICK HERE TO READ MORE FROM CARLY COOPERMAN