Donald Trump shocked election watchers on November 8, 2016, by winning states across the Midwest — states that were supposed to be part of Hillary Clinton’s “blue wall.” This year, Democrats have an enormous opportunity to start regaining ground in those same states.

Political pundits have wondered if Trump’s wins in Pennsylvania, Michigan, Wisconsin, and Ohio represented a realignment of American politics for good. Republicans in some of those states dreamed of turning them permanently red with big wins in the 2018 midterms.

But in the weeks before Election Day 2018, Democrats are poised for huge wins across the Midwest, a resurgence that seemed unimaginable just two years ago.

Incumbent senators in Ohio, Michigan, and Pennsylvania seem assured of reelection. Democratic Sen. Tammy Baldwin, a coveted target for Republicans, is leading by 10 points in Wisconsin, where Republican Gov. Scott Walker could finally lose a reelection campaign. And in Ohio and Iowa, states Trump won handily, Democratic candidates for governor have a narrow advantage in the polls.

Of course, polls do not guarantee election victories. After all, Democrats were polling well in the Midwest in 2016, too, before an undetected Trump wave won him the White House. All it would take is a small polling error, which happens all the time, to swing many of these races to Republicans once the votes are counted.

Still, no one factor explains this apparent Democratic strength. The minority party typically performs well in midterm elections. Democrats have particularly strong incumbents in Ohio and Pennsylvania. The Republican brand is tarnished in Michigan and Ohio over some state-specific scandals. But those variables only explain so much. Run-of-the-mill Democrats have big leads in Wisconsin, Pennsylvania, and Michigan.

Rather, these states have the right ingredients for a blue wave in 2018. Suburban, mostly white women seem to be drifting toward Democrats. Working-class whites, historically Democratic voters who broke for Trump, show signs of returning to their economically left-leaning roots. Strong black turnout would deepen the Democratic advantage.

The omens are good, and Democrats have reason to hope that 2016 was just an aberration. But, until the election returns come in, it is still only a hope.

The obvious reason Democrats suddenly look strong in the Midwest

It is a fact of American politics that voters seem to strive for balance: One party wins the White House in presidential years, and then the other party makes gains in the midterms two years later.

To some extent, the apparent swing in the Midwest simply follows that history. Wisconsin elected Walker governor two years after voting for Barack Obama. Ohio elected Democrat Dick Celeste governor two years after voting for Ronald Reagan. Voters do seem to like a partisan equilibrium.

“The Midwest is the most consistently competitive region of the United States, and it oscillates between the two parties,” Kyle Kondik, who follows elections at the University of Virginia’s Center for Politics and wrote a book on Ohio politics, told me. “Trump’s election may suggest a longer-term realignment toward Republicans given how white the Midwest is, but for the time being it remains hard to classify as being solidly in either camp.”

Some Democratic gains in the Midwest in 2018 were to be expected. Democrats look dominant in the Illinois governor’s race and in Minnesota’s Senate and governor elections, poised to score important victories in the bluest Midwestern states.

But there seems to be more happening than history repeating and blue-leaning states staying blue, according to Democratic and Republican operatives across the region. Democrats aren’t just shoring up the elections they were already expected to take. They also have a good chance to hold onto Joe Donnelly’s Indiana Senate seat, in the reddest state in the Midwest region.

The path to a big Democratic wave in the Midwest in 2018 runs through three voting blocs: Suburban Republican-leaning women who don’t like Trump, the white working-class Democrats who voted for the president, and black voters who are less likely to vote in off-year elections.

Democrats need to win back some Obama-Trump voters in 2018

The difficulty of the Democratic task can’t be overstated.

Take Ohio. In 46 of Ohio’s 88 counties, Barack Obama got at least 40 percent of the vote. Hillary Clinton hit that floor of 40 percent in just 13 counties. Or look at it this way: Obama lost the 50 smallest counties by 180,000 votes; Clinton lost them by 400,000 votes.

The rural white Democratic vote was never going to carry Democrats to victory in the Buckeye State or any of these states, but it was still important that Obama performed well enough in those areas to avoid an insurmountable deficit. In 2016, however, the bottom fell out. Clinton just couldn’t make up enough of the difference in Ohio’s major metropolitan areas of Columbus, Cleveland, and Cincinnati.

For the Democrats, winning in 2018 starts with a respectable showing in those rural, white areas.

“In Ohio, you have to do it all,” Ohio Democratic Party chair David Pepper told me. “There are not enough Democrats in our biggest cities to overcome a 73-27 loss in the rest of Ohio.”

In 2018, the party should be boosted by the presence of Sen. Sherrod Brown, a throwback Democratic populist, on the ballot. Cordray, an economic progressive in the Elizabeth Warren mold, is campaigning on a similar platform even if he doesn’t enjoy quite the same popularity or familiarity with the Ohio electorate as Brown does.

In a September Marist poll, Brown was winning 56 percent of independents, 70 percent of moderates and even 17 percent of conservatives. Education is maybe the most telling indicator of voter preference in the Trump era and Brown performed respectably with white non-college voters, with 42 percent of the vote.

“We’re not going to win every one of those voters back, but Sherrod Brown will win counties that Donald Trump won,” Pepper said.

In Wisconsin, it’s estimated there are 75,000 Trump Democrats. Yet according to Marist, Baldwin, the incumbent Democratic senator, is outpacing Republican Leah Vukmir in rural parts of the state. Even in the Fox River Valley, an industrial center in the Badger State, the Democrat holds a slim 2-point lead over the Republican, even though those voters still have a positive view of Trump, who has 55 percent approval rating there. Evers isn’t quite beating Walker in the same region, but he is trailing the Republican by just two points.

Trump’s brand of populism mixed up the usual economic breakdown between Democrats and Republicans, and that has made it more difficult for other Republicans to build off his success with Trump Democrats. Walker criticized the Trump administration’s tariffs on steel and aluminum and he distanced himself from the president’s immigration policies.

On tariffs particularly, Trump crossed ideological boundaries and appealed to white working-class voters. But other Republicans can’t seem to replicate his playbook, perhaps because it is so contrary to the usual business-accommodating GOP agenda.

“The Republican Party in Wisconsin didn’t do a thing to reach out to Trump voters for two years,” one GOP operative in the Midwest told me.

The Midwest also has a lot of suburban women who don’t like Trump

On the suburban front, Democrats felt buoyed by Danny O’Connor’s narrow loss to Republican Troy Balderson in the Ohio 12th special election in August. That district covers most of the northern Columbus suburbs and Trump won it by 12 points. The previous GOP Congress member won by 35 points. But O’Connor lost by just a single point, and he could beat Balderson in November.

“We have to make a run at some of these swing voters. Some are still Republicans. Some would say they’re independent. They would say, ‘The party left me,’” Pepper said. “These are not automatic votes for us. We have to have good candidates. But they seem to be open to our candidates in a way they wouldn’t have been six or eight years ago when they would have been perfectly content to vote for Mitt Romney.”

The same playbook applies in Wisconsin. There are roughly 75,000 Never Trump Republican voters, the GOP operative told me, using 2012 versus 2016 election results to calculate. Those cohorts will be critical in the governor’s race between Scott Walker and Democratic challenger Tony Evers, as well as the Senate election.

Suburban woman could be decisive across the Midwest: Marist found them breaking for Brown in the Ohio Senate race, 58 percent to 27 percent. In the Wisconsin governor’s race, women in the suburbs and small cities back the Democrat by a 56-42 margin.

In Michigan, Democratic gubernatorial candidate Gretchen Whitmer has consolidated an impressive 10-point lead over Republican Bill Schuette. She is pulling 10 percent of Republicans, according to a recent poll commissioned by the state chamber of commerce, while edging Schuette in the Detroit suburbs and the industrial western region of the state. She has a 14-point advantage with women.

The Midwestern GOP operative described a defining paradox for Republicans across these states: How do they appeal to those Trump Democrats, who might be less enthused without the big guy on the ballot, without alienating the suburban women who probably voted for Romney with no hesitation but abhor Trump?

“You see Republicans struggle with this: What do I give Trump supporters while showing independents and moderates I’m unique, I’m not responsible for the Trump circus,” the GOP operative told me.

Democrats need to finally turn out black voters in the midterms too

The last piece of the Democratic puzzle is motivating African-American voters, who overwhelmingly back Democrats when they do vote but don’t historically turn out with the same numbers in midterm elections as they do in presidential years.

Democrats already saw their support erode in 2016 where those voters live. In three of the biggest Midwest urban centers — Wayne County, Michigan; Milwaukee County, Wisconsin; and Cuyahoga County, Ohio — Hillary Clinton lost tens of thousands of voters compared to Obama.

She got 76,000 fewer votes than Obama in the Detroit area, 49,000 fewer votes in Cleveland, and 43,000 fewer votes in Milwaukee, according to 2016 voter data compiled by The Atlantic.

“That’s where Hillary lost the election,” the GOP operative told me. “Obama put up such crazy numbers in Milwaukee, but Hillary depressed voter turnout in those areas.”

In 2008 and 2012, black voters actually outpaced whites in the number of eligible voters who voted. But for years, in midterm elections, the pattern has been that white voters turn out more consistently than black voters.

Democrats know they need to close that gap as much as possible, or even winning back white working-class voters and winning over suburban Republican-leaning women might not be enough to win in the 2018 midterm elections.

“There is that historic concern. Those voters fall off during the midterms,” Pepper said. “They need to feel inspired to vote as well.”

The other variable particularly for black voters is Republican efforts to restrict voting. In Ohio, for example, Republicans have instituted a policy to remove voters’ names from the roles if they haven’t voted in the two most recent federal elections. Wisconsin also has a strict voter ID law, and a post-2016 analysis found the law discouraged voting in the Badger State for the presidential election.

The other very specific reasons Democrats could win big in 2018

Of course, while our politics are increasingly nationalized, state-level concerns have also given Democrats an advantage in 2018. Sherrod Brown has built a unique populist brand in Ohio. Bob Casey’s family is the stuff of Pennsylvania legends.

Republicans have also damaged their own standing in some of these states after nearly a decade of total control. In Michigan particularly, Republican Gov. Rick Snyder’s botching of the Flint water crisis led to his approval ratings plummeting, and the relationship between him and Bill Schuette, the GOP attorney general running to replace him, has been strained. Whitmer is in good shape to win the governor’s race and her party could also take back the Michigan House, once thought out of reach.

The Ohio House GOP Speaker was forced to resign and now faces an FBI corruption investigation, and a charter schools controversy also haunts the GOP majority. The state Republican party is quietly enduring something of an identity crisis: Its current leader, term-limited Gov. John Kasich, is Trump’s fiercest Republican critic, but the president clearly has a lot of fans in the state after beating Hillary Clinton here by nearly 10 points.

“There may be an ethical problem — not with the governor but with the Republican brand,” Kondik told me earlier this year. “Democrats have sometimes been aided in big elections in Ohio by GOP ethical and corruption problems.”

Walker has towered over Wisconsin politics for eight years. His union-busting crusade brought a recall election in 2012, but Walker beat back the Democratic anger and won again in 2014. He now wants a third term as he seeks to institute Medicaid work requirements and warns the state could become dangerous if Democrats win. But Trump’s approval rating is down here, and a tech development drive pursued by the Walker and Trump administrations has been divisive.

In Iowa, Republican Gov. Kim Reynolds looks vulnerable to a well-funded, business-minded Democrat in Fred Hubble. The Hawkeye State has soured on Trump, and the president’s trade war isn’t helping matters. But Iowa’s privatization of Medicaid under Reynolds is a big issue hobbling her reelection bid, and, right now, and Hubble is polling a few points ahead of her here in late October.

The biggest risk for Democrats is another huge polling miss in the Midwest

The biggest fear for Democrats in the Midwest in 2018 is that the polls are just wrong.

Hillary Clinton appeared to hold a solid lead in Wisconsin, Pennsylvania, and Michigan, but then an undiscovered batch of Trump voters showed up at the polls. The polls missed by nearly 7 points in Wisconsin, compared to the final tally, and by 5 points in Ohio. Trump’s support was underestimated by roughly 4 points in Michigan, Pennsylvania, and Minnesota, a post-election autopsy published by the American Association for Public Opinion Research found.

The reasons for that polling miss are varied, but one underlying consistency is that pollsters didn’t identify the white, less educated voters whom Trump won overwhelmingly.

The polls “clearly underestimated Trump’s support in the Upper Midwest,” the autopsy’s authors concluded.

Among the causes, they named an underrepresentation of less educated voters. “In 2016 there was a strong correlation between education and presidential vote in key states,” the autopsy read. “Many polls — especially at the state level — did not adjust their weights to correct for the overrepresentation of college graduates in their surveys, and the result was overestimation of support for Clinton.”

Polls miss all the time. There is nothing Democrats can do to avoid that fact. But by pursuing a multi-pronged strategy to win back Trump Democrats, win over suburban Republicans, and turn out black voters, they can give themselves a chance again in the Midwest.