Bernie Sanders now enjoys a sizable lead in Wisconsin among likely Democratic primary voters, according to a new statewide poll.

Sanders has more than twice the support of any other Democrat in the field in a survey done Feb. 11-20 by the Elections Research Center of the University of Wisconsin-Madison.

The survey was taken after contests in Iowa and New Hampshire (where Sanders got the most Democratic votes) but before Saturday’s Nevada caucuses, which Sanders won handily.

Wisconsin’s presidential primary is not until April 7. More than two dozen states will vote between now and then.

Among registered voters who plan to vote in Wisconsin’s Democratic primary, Sanders led in the poll with 30%. The rest of the field was far back and closely clustered: Joe Biden and Michael Bloomberg were each at 13%, Elizabeth Warren and Pete Buttigieg were at 12% and Amy Klobuchar was at 9%.

The survey was conducted for the university by YouGov, a firm that does online interviews in the U.S. and abroad. It draws a demographically representative sample from a much broader pool of people who have agreed to take part in the company’s research. The sample for this poll was 1,000 registered voters. The Wisconsin State Journal is a partner in the poll.

The survey found little separation in Wisconsin in general election matchups between Republican President Donald Trump and his potential Democratic opponents.

Trump trailed each Democrat by 1 or 2 points, well within the survey’s margin of error.

Most polling has painted a very competitive picture in the battleground state of Wisconsin. In the most recent Marquette Law School poll taken Jan. 8-12, Trump trailed Biden by 4 points and Sanders by 1 point but led Warren by 3 and Buttigieg by 2. A Fox News poll released in early January showed Trump trailing narrowly in Wisconsin against the top Democrats.

But a Wisconsin poll released Thursday by Quinnipiac University produced a very different set of results, showing Trump leading every one of his Democratic opponents in Wisconsin by at least 7 points.

RELATED:Paul Ryan says a Bernie Sanders nomination would help GOP win back the U.S. House

It’s not unusual for polls that use different survey methods to deviate from each other, though the gap in this case is a fairly large one.

Part of the explanation may be that these surveys captured a different partisan mix of voters. In the Quinnipiac poll, 32% of those surveyed were Republicans and 26% were Democrats (with the rest independents). In the new UW-Madison poll, 35% were Democrats and 30% were Republicans. In last month’s Marquette poll, 28% were Republican and 26% were Democrats.

The UW-Madison poll and the Quinnipiac poll differed in another way.

Each conducted simultaneous surveys of three key battlegrounds — Wisconsin, Michigan and Pennsylvania — that were won by Trump in 2016 by less than a percentage point.

In the Quinnipiac survey, the Wisconsin results were much more favorable to Trump than the results in Michigan and Pennsylvania (where Trump trailed his Democratic rivals).

In the UW-Madison survey, there was a lot less separation among the three states, with Trump essentially even or modestly behind in matchups with most Democrats. Of the three, Pennsylvania was the worst state for Trump in the Quinnipiac polls. Michigan was the worst for Trump in the UW-Madison polls.

“All three states are up for grabs in 2020,” said Barry Burden, political scientist at the University of Wisconsin-Madison and director of its Elections Research Center.

Trump’s job approval was 44% in Wisconsin, 45% in Pennsylvania and 43% in Michigan in the UW poll.

In the Democratic nominating fight, the UW poll found Sanders also leading the field in Michigan and Wisconsin, though by smaller margins than in Wisconsin.

Combining the three states, it found Sanders leading his fellow Democrats among whites and Hispanics and Biden leading among African Americans. It found Sanders far ahead with voters under 30, and Bloomberg and Biden leading among voters 65 and older.

Michigan’s primary is in March. Pennsylvania’s primary is not until April 28.