The blue wall battlegrounds will be won or lost on the economy. Here's where Harris stands in these critical states.

• Michigan, Pennsylvania, and Wisconsin will play a pivotal role in the upcoming general election.
• The trio of blue wall states offer promise to Vice President Harris and former President Trump.
• Trump has an edge on the economy, but Harris has made major inroads on the issue in recent weeks.

As Vice President Kamala Harris eyes an electoral path that offers the best opportunity for victory, the "blue wall" states of Michigan, Pennsylvania, and Wisconsin are front and center for Democrats.

It was in these three states where Donald Trump's economic message broke through in 2016, with the Republican making inroads with union members, older voters, and independents. And that message was enough to throw former Secretary of State Hillary Clinton off course — in states where most Democrats had expected her to win.

Harris is looking to avoid a repeat of her party's mistakes.

After the vice president launched her campaign in July, one of her first major appearances was in West Allis, Wis., a suburb of Milwaukee. She's worked to rally union workers — a key voting bloc — around her campaign. And Minnesota Gov. Tim Walz has added a touch of the Midwest to the Democratic ticket.

But will it be enough?

The race between Harris and Trump remains very close in the swing states, with both candidates jostling for support among voters by promoting their plans to tackle inflation, promote energy production, strengthen manufacturing, and build more housing.

Here's a look at the current state of play in Michigan, Pennsylvania, and Wisconsin, where voters are poised to determine the next occupant of the White House.

Wisconsin is as competitive as ever

In 2016, Clinton lost Wisconsin by less than one percentage point. And four years ago, President Joe Biden narrowly won the state by roughly 20,000 votes out of nearly 3.3 million ballots cast.

Given the closeness of previous presidential races, Harris has been a frequent presence in the state.

In August, Harris campaigned in Eau Claire and Milwaukee. In September, she stumped for votes in Madison. And in early October, she campaigned in Ripon — the birthplace of the Republican Party — alongside former Wyoming GOP Rep. Liz Cheney.

Harris' visits have been targeted at key groups, particularly base Democratic voters, women, independents, union members, and disaffected Republicans.

And the economy is at the top of mind for voters.

Harris has leaned into the Biden administration's work to boost jobs in the manufacturing sector. Her campaign has touted the CHIPS and Science Act, which the administration pushed for to jumpstart semiconductor manufacturing in the US. And she's been vocal about her plan to provide $25,000 in down-payment assistance to first-time and first-generation homebuyers, a proposal that has real appeal among Gen Zers and millennials who've been priced out of many housing markets.

At this juncture, the race in Wisconsin remains highly competitive.

The latest Marquette University Law School poll showed Harris leading Trump by a four-point margin (52% to 48%) among likely voters.

Meanwhile, a Quinnipiac University poll showed Trump ahead of Harris 48% to 46% among likely Wisconsin voters. In that survey, voters favored Trump over Harris by nine points (53% to 44%) when asked which candidate would be better on economic issues.

The fight for union members in Michigan

For decades, labor unions have largely been viewed as reliably Democratic. But there are caveats to this dynamic.

Leaders in unions like the AFL-CIO have largely backed the Democratic Party. And their ties to Biden have been an enduring part of the administration's work to address issues regarding prevailing wages and project labor agreements.

But among the rank and file, support for Democrats isn't a given.

In Michigan, Pennsylvania, and Wisconsin, Trump in 2016 successfully peeled off blocs of union workers. Some of them switched to Biden in 2020, which allowed the president to flip all three states back into the Democratic column that year.

However, some of these voters remain undecided about Harris, who lacks the sort of relationship that Biden had cultivated with working-class voters in these states. And Trump's economic pitch — where he's reiterated his desire to revive the manufacturing sector despite Harris' work on the issue alongside Biden — has been an effective draw for some members.

Peter Loge, an associate professor and the director of the School of Media and Public Affairs at George Washington University, told Business Insider that another reason for Trump's inroads with union workers is his strong standing with male voters.

"A lot of unions are male dominated and Trump is doing very well among men," he said. "There are simply fewer women in a lot of those unions."

But Loge also pointed to a newly-released Emerson College poll, which showed that Harris' union support varied by state. In the survey, Harris had a 26-point lead with Wisconsin union households and a ten-point edge with Michigan union households, but she trailed Trump by ten points with this group in Pennsylvania.

This year, the Teamsters declined to endorse Harris or Trump, which marked the first time since 1996 that it had not issued a presidential endorsement. (Several local Teamsters unions announced their support for Harris.)

In Michigan, the transition to electric vehicles (EVs) has become a significant issue in the presidential contest, and particularly in the state's marquee US Senate race between Democratic Rep. Elissa Slotkin and former GOP Rep. Mike Rogers.

Trump has accused Harris of seeking to implement an EV mandate, which she has vehemently denied.

"I will never tell you what kind of car you have to drive," Harris told attendees at a Flint, Mich., campaign event earlier this month. "But here's what I will do: I will invest in communities like Flint, which helped build the auto industry and the UAW."

Shawn Fain, the United Auto Workers president, told reporters on Thursday that the repeal of electric vehicle investments — which Trump has floated — would result in lost jobs.

"It's factories all over the United States, and it's supply chain factories all over the United States that are being put in place now," Fain said. "So you're talking hundreds of thousands of jobs that Donald Trump is just writing off."

For much of September, Harris boasted polling leads in the state. But Michigan Gov. Gretchen Whitmer, a Harris ally, argued at the time that the vice president didn't have a sizable advantage in the state.

David Dulio, a professor of political science and the director of the Center for Civic Engagement at Oakland University, told BI that Harris' performance in Michigan has so far been "solid."

"Harris hasn't done anything to grasp control and make it a done deal in Michigan," he said. "And she also hasn't done anything to sort of lose it, and I think that's reflected in the polls, where every one of them is within the margin of error."

The latest New York Times/Siena College poll had Harris ahead of Trump by one point (48% to 47%) among likely Michigan voters. But Quinnipiac's newest poll gave Trump a four-point advantage (51% to 47%) among likely voters in the state, a reversal from last month, when Harris led by five points (50% to 45%).

In the Quinnipiac poll, Michigan voters gave Trump an eight-point edge (53% to 45%) on the economy. But in recent polls, Harris has made up considerable ground on the issue — a sign that she's found success in forging some separation from Biden.

It's a shift that could also boost Harris in Pennsylvania, which is a critical state for her campaign. Biden won the state narrowly in 2020, besting Trump by one percentage point.

From Philadelphia and Pittsburgh to Johnstown and Wilkes-Barre, Harris is aiming to bring together a coalition of union workers, suburbanites, young people, women, and minority voters who fueled Biden's victory four years ago.

Harris has dismissed Trump's attacks on her energy record, as she's firmly said she wouldn't ban fracking in the state. And she's aiming to win over voters — especially union workers — in smaller cities where Trump found success in 2016.

The latest Quinnipiac poll gave Harris a 49% to 46% advantage over Trump among likely Pennsylvania voters.

But when it came to economic matters, Pennsylvania voters favored Trump over Harris by only two points (49% to 47%), another sign that voters have warmed up to some of her plans.