President Donald Trump trailed Democratic candidates Joe Biden and Bernie Sanders in hypothetical matchups but was tied with Elizabeth Warren and Kamala Harris, according to Wednesday's Marquette University Law School Poll.

"We're only in the second inning," poll director Charles Franklin cautioned.

He added: "These numbers are movable things on where we stand today but not predictions of the final outcome."

Wisconsin will be under a microscope for 14 months as the candidates battle in what could be the key state that unlocks the electoral college puzzle.

Wednesday's numbers provide a baseline for what will undoubtedly be a frenetic campaign, which will reach a high point of drama in Milwaukee with the Democratic National Convention next July.

Biden, the former vice president, led Trump by 51% to 42%, while Sanders, the Vermont senator, led Trump by 48% to 44%, close to the survey's margin of error.

Warren, the Massachusetts senator, and Trump were tied at 45% each. Harris, the California senator, and Trump were tied at 44% each.

There's a battle brewing for Wisconsin's April Democratic presidential primary, with Biden the first choice of 28% of those surveyed, Sanders at 20%, Warren at 17%, South Bend Indiana Mayor Pete Buttigieg at 6% and Harris at 3% All other candidates registered 2% or less.

Interestingly, Warren was the second choice of 20%, with Biden at 18% and Sanders at 13%.

Biden was viewed favorably by 70% of Democratic primary voters and unfavorably by 20%; Sanders was at 63% favorable and 21% unfavorable.

Warren was viewed favorably by 53% and unfavorably by 12%, but 34% either hadn't heard enough or don't know enough about her to have an opinion.

Buttigieg was viewed favorably by 37% and unfavorably by 7% while Harris was viewed favorably by 35% and unfavorably by 14%.

"Many voters are not yet acquainted with the field," Franklin said.

Trump's job approval rating stood at 45% compared with 53% disapproval. But when rating his job performance on how he's handling the economy, Trump's approval was at 49% against 50% disapproval.

Naturally, there was a partisan split on Trump. Eighty-eight percent of Republicans approved of Trump's handling of the economy, compared with 9% of Democrats and 43% of independents.

If the economy is key, the poll had some good news for the president.

Thirty-seven percent said the economy has gotten better, 25% worse and 34% said it has stayed the same.

But asked how the economy would look over the next 12 months, 26% expected it to get better but 37% said they expected it to get worse, while 33% said they expected it to stay about the same.

Republicans remained quite optimistic about the economy, with 41% saying it would be better. Among Democrats, just 12% said the economy would get better.

Asked about tariffs, which have become a key economic lever used by the Trump administration, 30% said they helped the economy and 46% said they hurt.

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On water quality, an important issue in some areas of the state, 21% said they were very concerned about the safety of the water supply in their community, 22% were somewhat concerned while 57% were not too concerned or not at all concerned.

Asked how the state was doing in protecting public drinking water, 52% said excellent or good, while 39% said fair or poor.

Seventy-four percent said the state should provide aid for lead pipe replacement, while 16% said the homeowner should pay for the replacement.

Democratic Gov. Tony Evers remains popular even after his first budget tussle with the Republican-led Legislature. His job approval rating stood at 54% compared with 34% disapproval.

Even the state Legislature could take away some good news, with 52% job approval and 38% disapproval.

More than half those surveyed couldn't offer an opinion on whether they had a favorable view of the Republican legislative leaders.

Senate Majority Leader Scott Fitzgerald was viewed favorably by 19% and Assembly Speaker Robin Vos had a 20% favorable rating. They were both viewed unfavorably by 20%.

Fifty-five percent said Wisconsin is headed in the right direction while 37% said it was on the wrong track.

The survey of 800 Wisconsin registered voters was conducted August 25-29. The margin of error was plus or minus 3.9%.

For questions involving only Democrats, the margin of error was plus or minus 5.3% While a half sample was used for some issue-related questions with a margin of error of plus or minus 5.6%.