This Is the Biggest Reason Why a Blue Wave is Probably Coming

There are lots of reasons to believe Democrats are about to crush the midterm elections. Donald Trump’s average job approval is below 40 percent, about 5 points lower than it was in the 2018 midterms, which were deemed a “Blue Wave.” His authoritarian antics continue to dominate media coverage, as does seemingly corrupt behavior from him and his family. Democrats are ahead in the generic congressional ballot poll average by nearly 9 points, matching the national popular vote margin for the 2018 House elections. In September polling of Senate races, Democrats lead in six states with Republican-held seats, more than the four needed to take control. Gas and food prices remain high, which the public broadly blames on Trump’s ham-fisted tariffs and blunderbuss war with Iran. 

There are millions of reasons to believe Republicans are going to hold off a Blue Wave: specifically, the hundreds of millions of dollars they are flooding into political advertising to paint Democratic candidates as radical socialists. As Democrats need wins in states and districts where Trump won comfortably in 2024, the right-leaning voters who will determine the outcomes may well be swayed by the negative advertising avalanche. Furthermore, the Democratic margins in most Senate polling are usually within the margin of error, and there is plenty of precedent for Republicans to outperform polls on Election Day.  

But one factor may outweigh the rest: the decline in real disposable income.  

Real disposable income measures how much money people have after taxes, adjusted for inflation. Seth Masket, the political scientist who now publishes a Substack newsletter has long tracked the correlation between real disposable income and midterm election outcomes. As The Atlantic’s Derek Thompson observed about Masket’s research back in 2010, “It’s not perfect correlation, but the trend is clear. When folks feel richer, they reward the party in power.” This May, Masket offered a midterm forecast largely based on the specific metric he uses, “growth in per capita real disposable income between the second quarter of the year before the election and the first quarter of the election year,” which came in at a limp 0.4 percent. The model projected a 46-seat net gain for House Democrats, though even Masket said he would consider it surprising if that exact number came to pass.  

Allow me to add a data point: the second quarter of the election year. 

Per capita real disposable income took a big hit in the second quarter of 2026, with growth coming in at negative 0.4 percent compared to the prior quarter. 

And what happened just before the second quarter began? Donald Trump attacked Iran, and oil prices skyrocketed. 

If we look at growth in per capita real disposable income from the 3rd quarter in the year before a midterm to the 2nd quarter in the year of the midterm, the 2025-2026 number is also negative: -0.5 percent.  

Any such decline is unusual. We’re about to hold the 20th midterm election since 1950. In only four of these, from the period of third quarter to the second quarter, did per-capita real disposable income shrink.  

Two of those midterms, 1958 and 1974, tie for the biggest Blue Waves of the last 75 years, each netting Democrats 48 House seats. A third was in 2022 during the Joe Biden presidency, when red-hot inflation chewed up paychecks, but Masket notes it as a massive outlier, with the president’s party coughing up only nine House seats. He attributes the limited losses to a slew of Trump-backed extremist candidates baselessly flogging election fraud and backlash over the right-wing Supreme Court ending Roe v. Wade. I would add that the worst of the inflation spike had ended; 2022’s second quarter decline was not as bad as the preceding four, and the following quarter was positive. In other words, the trajectory was moving in the right direction.  

The fourth case is the 1954 midterm, which produced a relatively modest net gain of 18 for the opposition Democrats, slightly below the post-World War II midterm election average for the party not occupying the White House. That year is like this year in one other respect: ahead of Election Day in 1954, Democrats were already close to a House majority with 213 seats, so 18 more than did the trick to gain control. A party can have a tougher time scoring big gains when it already has a good number in hand. Today, Democrats start with a similar 215, a sound reason to contain expectations. 

So I won’t predict a number of Democratic pickups based on the downward trajectory of real disposable income alone. But to apply some Occam’s razor logic, a simple explanation for all the wildly Democratic-friendly poll data is that the people are losing disposable income and they blame—and with good reason thanks to Trump’s tariffs and war with Iran—the party in power.  

Moreover, if the general electorate is angry and attributes weakened purchasing power to Republican policies, then Republicans will have a difficult time getting them mad about something else—whether it’s Abdul El-Sayed campaigning with a radical Twitch streamer or James Talarico’s record of defending transgender rights—no matter how much money they spend. Amy Walter, of The Cook Political Report with Amy Walter, recently shared that, “Democratic and Republican operatives we spoke with this week told us that, at this point, attack ads against Democrats were not yet ‘moving the needle’ in the races they were tracking. Democratic candidates, for the most part, appear to be withstanding the deluge of advertising so far.” 

The decline in disposable income is not happening in a vacuum. As noted earlier, Trump’s average job approval is below 40 percent, worse than it was ahead of the 2018 midterm when Democrats netted 41 House seats (but net lost two Senate seats). Yet he is as incorrigible as ever, generating negative headlines—and free footage for Democratic admakers—on a daily basis. Instead of alleviating cost pressures on households heading into the fall campaign season, Trump escalated the trade war with Canada, shrugged off his failure to end Iran’s control of the Strait of Hormuz, and has stood by impotently as the Saudi Arabia-Yemen conflict spirals out of control and further chokes oil supply lanes. The swingy Latino vote is recoiling at Republicans because of Trump’s wanton mass deportation policies and violent—sometimes deadly—behavior of his immigration enforcers. 

Because Trump is prone to publicly excoriating Republicans who criticize him, including outright opposition in primaries, few Republicans on the ballot have earned reputations of independence; only a handful have begun, quite belatedly, to distance themselves. Republicans cannot change many factors shaping the political landscape at this stage of the race, while what a candidate can control—the ability to forge an individual identity and local connections beyond party affiliation—Trump has severely limited.  

Might faulty polls be overstating Democratic support? Might the Republican ad blitz eventually draw blood? Might unknown scandals derail promising Democratic fresh faces? Of course. Any assertion of certainty in the outcome is foolhardy. But when Americans have less money in their pocket, the party in power usually pays a steep political price. 

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