Polls in two key House races in the Midwest taken before and after Democrats’ switch from President Joe Biden to Vice President Kamala Harris could reveal how the 2024 elections have evolved in the last 10 days and provide a window for the new normal. 

A survey taken in early July in the wake of Biden’s disastrous debate performance showed the president underperforming his 2020 vote totals in Michigan’s 7th District, with Democratic candidates performing better than Biden in the House and Senate races. But a new poll taken in Ohio’s 9th District days after Harris sewed up the Democratic nomination showed the vice president outperforming Biden’s 2020 vote share and longtime House and Senate incumbents with sizable leads with three months to go in the election. 

These are just two polls in two congressional districts in a vast landscape of states, districts and races, but they provide a glimpse into the state of the election at two key moments in time. More time will tell whether the Ohio survey is an outlier or part of a larger, positive trend for Democrats. 

The presidential race

Biden beat President Donald Trump 49.4-48.5 percent in 2020 in Michigian’s 7th, as part of his narrow victory statewide. But things looked dire for Biden in the Lansing-based district after he appeared to freeze and at times gave garbled answers in a June 27 debate. An early July poll showed Biden losing to Trump by 8 points, 50-42 percent, in a head-to-head matchup. 

The potential for a loss like that in the 7th not only portended a statewide loss for Biden in a must-win state, but made it more difficult for Democrats to hold the open House seat and win the competitive U.S. Senate race. That Biden underperformance and potential drag on down-ballot races around the country caused Democratic elected officials to sound the alarm and call for the president to drop out of the race. 

At this point, it looks like the Democratic pressure campaign is having the desired result, at least at the top of the ticket. Along with a boost in fundraising, volunteers and energy at rallies, there’s some initial evidence that Harris can reach or exceed Biden’s 2020 performance. 

A late July poll in Ohio’s 9th showed Harris running even with Trump at 46 percent in a Toledo-area district where Trump finished ahead of Biden by 3 points in 2020. Even if the poll was taken at a time when Democrats were supercharged by the switch from Biden to Harris and by past comments about childless women by GOP vice presidential nominee JD Vance, the fact Harris is even coming close to Biden’s 2020 mark is great news for Democrats, considering Biden was struggling to recreate the magic of the last race. 

Both surveys were conducted by Noble Predictive Insights for Inside Elections. The poll of 532 likely general election voters in Michigan’s 7th was conducted July 8-11 via text and live callers and had a margin of error of plus or minus 4.4 percentage points. The poll of 435 likely general election voters in Ohio’s 9th was conducted July 22-24 via text and live callers and had a margin of error plus or minus 4.7 percentage points. 

While it’s too early to know whether Harris will do measurably better with independent voters than Biden, there’s qualitative and quantitative evidence that she’s consolidating Democratic support in ways Biden could not. 

Beyond the palpable excitement, there is some survey data. In the Michigan poll, Biden received support from 90 percent of Democrats while Harris received support from 96 percent of Democrats when a Harris vs. Trump matchup was even more hypothetical. In the more recent Ohio survey, Harris received support from 97 percent of Democrats. If that ends up being the case nationwide, it would be the highest level of partisan voter allegiance in recent history. 

House races

If Harris can come close to, match or exceed Biden’s 2020 performance, it not only puts Democrats back in the game to potentially hold the White House, but gives them a fighting chance to win back the House and hold the Senate. Because of the high correlation between presidential, Senate and House outcomes, a strong top of the ticket is important. 

In the Michigan survey, which was mostly good news for Republicans, Democrats’ fate looked tied to Biden’s slumping campaign. Biden received 42 percent in the survey, while Democrat Curtis Hertel received 41 percent in the House race against Republican Tom Barrett, who got 48 percent. The seat is open because Democratic Rep. Elissa Slotkin is running for retiring Democratic Sen. Debbie Stabenow’s seat. 

In the Ohio survey, which was mostly good news for Democrats, the correlation was also strong. Even though longtime Rep. Marcy Kaptur had a 10-point advantage over Republican Derek Merrin, she was below 50 percent and her share of the vote (47 percent) was similar to Harris’ 46 percent. If Merrin is able to raise his name ID and consolidate GOP support, he could close a large part of that gap, although the 21-term congresswoman has a sizable fundraising advantage. 

Michigan’s 7th District is rated Toss-up by Inside Elections while Ohio’s 9th is rated as Tilt Democratic. Both seats are probably must-wins for Democrats, who need to gain four seats for a majority. Inside Elections currently projects a range of a Democratic gain of five seats to a Republican gain of five seats. 

Senate races

The polls also shed light on two key Senate races. Similar to candidates nationwide, Democrats in Michigan and Ohio were outperforming the top of the ticket in two key congressional districts, but not by an overwhelming margin. 

In Michigan, Slotkin was running virtually even with former Rep. Mike Rogers, 47-48 percent. That was 5 points better than Biden, who was the presumptive nominee at the time. Slotkin and Rogers each face challengers in Tuesday’s Michigan primaries, but have the backing of their parties’ national Senate committees and lead in fundraising. In Ohio, Democratic Sen. Sherrod Brown led GOP car dealer Bernie Moreno by 13 points, but the senator’s 49 percent was just 3 points more than Harris. 

For some context, Slotkin can win statewide with a close race in the 7th District. Democratic Sen. Gary Peters carried the district by a slim, 0.4-point margin in his 1-point reelection win in 2020, but it also wasn’t his home district the way it is for Slotkin. The 7th District has been a bellwether for the state, according to Jacob Rubashkin of Inside Elections. In all three state-level elections in 2022 — for governor, attorney general and secretary of state — the statewide margin was within 1 point of the 7th District margin. That was also the case in the 2018 and 2020 Senate contests, which Democrats narrowly won.

While Brown’s margin in Ohio’s 9th looked sizable in a district that Trump won in 2020, it probably needs to be that way for the senator to win statewide. In 2018, Brown carried the 9th by 17 points, but won statewide by 7 points, so he could likely afford to win by less in the district. The poll showed Moreno still must work to get known and to consolidate GOP voters. 

The Ohio Senate race is rated as Toss-up by Inside Elections and Michigan’s is rated Tilt Democratic. Both races are must wins for Democrats to maintain control of the Senate. Because Republicans are very likely to win the West Virginia seat being left behind by Sen. Joe Manchin III, Democrats have to win all of their remaining seats and win the White House to keep control. Inside Elections’ current likely outcome range is a Republican gain of one to three seats.

Nathan L. Gonzales is an elections analyst with CQ Roll Call.