Democratic presidential nominee Joe Biden maintained his lead over President Donald Trump in the latest poll by Marquette University Law School, this one coming with less than a month before Election Day.

Biden led Trump 46-41 among likely voters in the survey, which was Marquette's first since the presidential debate. Another 4% said they would vote for Libertarian presidential candidate Jo Jorgensen, while 8% said they were undecided.

In Marquette's September poll, Biden led Trump 47-43 among likely voters with 4% supporting Jorgensen and 7% undecided.

Overall, the poll interviewed 805 registered Wisconsin voters. The overall sample had a margin of error of 4.2 percentage points.

Questions asked of 700 likely voters had a slightly higher margin of error of plus or minus 4.6 percentage points. Put differently, a candidate would have to be leading by more than 9% to be outside of the survey's margin of error.

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The poll was conducted from Sept. 29 through Oct. 4, meaning some of it took place before the president tested positive for COVID-19 and some took place after.

In terms of Biden's margin, the poll was remarkably consistent with other recent surveys. In the past five Marquette polls dating back to early May, Biden's margins over Trump have been 5, 4, 5, 6 and 4 percentage points.

"Once again, we've seen all kinds of events take place this year and so many events just in this week that we were in the field, but not very much changed," said Marquette pollster Charles Franklin.

Among registered voters, 41% said Biden did the best job in the first presidential debate, 20% said Trump did best, and 14% said both did badly. Twenty-one percent said they didn't pay much attention.

Asked more broadly about their opinions of the candidates, 42% had a favorable view of Trump, while 53% viewed him unfavorably. For Biden, 48% had a favorable view compared to 45% unfavorably, which was the first net positive favorable rating for either candidate this year.

This was also Marquette's first poll of Wisconsin voters released since the death of U.S. Supreme Court Justice Ruth Bader Ginsburg and the subsequent push by Trump and U.S. Senate Republicans to replace her with Judge Amy Coney Barrett before the election.

Forty-four percent of those polled said the Senate should vote on Barrett's nomination this year, while 51% said the Senate should wait until after the election. When broken down by partisan affiliation, 81% of Republicans said the vote should happen now, while just 8% of Democrats favored that. Independent voters were split on the question.

Marquette also asked voters several questions about the COVID-19 pandemic, including steps taken to fight it.

The poll found 72% supported requiring masks in public places compared to just 26% who were opposed. Those numbers are slightly higher than in August, when 69% supported a mask mandate and 29% opposed it.

The latest findings come as Republican lawmakers are supporting a lawsuit that seeks to overturn a statewide mask mandate issued by Gov. Tony Evers.

"Solid majorities in every region support the mask requirement," Franklin said.

Marquette found support for a mask mandate exceeded 60% across all regions of the state. Broken down along partisan lines, 47% of Republicans supported a mask mandate while it was backed by 66% of independents and a near-unanimous 98% of Democrats.

The poll found 47% favored a return of Big 10 football at the University of Wisconsin-Madison. Forty percent opposed it.

Just 41% said they approved of Trump's handling of COVID-19, while 52% approved of Evers' handling of the pandemic.

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