President Donald Trump trails his potential Democratic rivals in Pennsylvania and Michigan and leads outright in Wisconsin, according to a new Quinnipiac University poll of the three Rust Belt swing states that cemented the president's 2016 victory.


Trump is within close range of the Democrats in Pennsylvania and Michigan, the survey shows.


"Three different states, three different scenarios," said Mary Snow, a Quinnipiac University polling analyst. "One constant: the economy."


In Pennsylvania, Trump trails Joe Biden, Amy Klobuchar, and Mike Bloomberg — all moderates — by six to eight percentage points among registered voters, while Bernie Sanders, Pete Buttigieg, and Elizabeth Warren are edging him out by narrower margins.


In Michigan, Biden, Bloomberg, and Sanders are narrowly leading the president, while Warren, Buttigieg and Klobuchar are nearly tied with him. In Wisconsin, Trump tops the Democratic contenders by around 7% to 11% in hypothetical head-to-head matchups.


Though voters in all three states held positive views of the economy overall, more than half of registered voters in Pennsylvania and Michigan have negative opinions of Trump, the poll finds. In Wisconsin he has a 50% positive rating.


Until Trump carried them, the three states had voted reliably for Democratic nominees in presidential elections, so much so that they were dubbed part of the party's Electoral College "blue wall." Both parties consider them critical in 2020.


Beating Trump is the top issue for Democrats in most polls, and voters in early nominating contests have sent mixed messages, though Sanders, a self-identified democratic socialist, has been surging. Biden, Klobuchar, and Buttigieg have sold themselves as the best able to win states such as Pennsylvania, and thus, the White House.


Amid the glimmers of good news for Democrats in the poll, if the Democratic candidate for president flipped Michigan and Pennsylvania but lost Wisconsin, Trump would still be reelected.


"These Wisconsin numbers are a red warning sign for Democrats that rebuilding the 'blue wall' in 2020 may not be so easy," Snow said. "But it's a long way to November."


Overall, registered voters polled cite the economy as their most important concern heading into the 2020 election. Twenty-nine percent of voters in Pennsylvania said it was their top concern, while 35% said it was their top issue in Michigan and 31% in Wisconsin.


When breaking down results by party, things look much different.


"Voters citing the economy as the number-one issue are voting overwhelmingly for President Trump," Snow said. "But the exact opposite is true for voters who say health care or climate change are their top issues."


When it comes to the economy, most voters have a sunny view. 57% of voters in Pennsylvania say they are better off financially than in 2016, while 62% in Wisconsin say they are in a better spot and 55% in Michigan think they are better off.


Results were obtained via telephone interviews with self-identified registered voters in each state conducted between Feb. 12 and Feb. 18, on both landlines and mobiles. Numbers were randomly dialed, and the results in each state are subject to a sampling error margin of plus or minus 3.4 percentage points, Quinnipiac said.


Pennsylvania will hold its Democratic primary April 28. Michigan votes March 10, while Wisconsin casts primary ballots April 7.


Verma covers N.J. politics for The Philadelphia Inquirer. Distributed by Tribune Content Agency, LLC.