A poll from Emerson College of Wisconsin voters finds Vermont Sen. Bernie Sanders (I-VT), an independent who caucuses with Democrats and is running as a Democrat for president in 2020, leads the pack of Democrats running for president in the important battleground rust belt state.

Sanders, at 39 percent, towers over his next closest potential competitor former Vice President Joe Biden–who is down at 24 percent in the Democrat primary poll of Wisconsin voters. Sen. Elizabeth Warren (D-MA) comes in third with 14 percent, while former Rep. Robert Francis “Beto” O’Rourke (D-TX) places fourth with 6 percent. Trailing them are Sens. Kamala Harris (D-CA) with 5 percent, Amy Klobuchar (D-MN) with 4 percent, and Cory Booker (D-NJ) with 2 percent.

Andrew Yang, Sen. Kirsten Gillibrand (D-NY), and former South Bend, Indiana, mayor Pete Buttigieg each clock in with 1 percent, while former Housing and Urban Development (HUD) Secretary Julian Castro, Rep. Tulsi Gabbard (D-HI), former Colorado Gov. John Hickenlooper, and Washington Gov. Jay Inslee all fail to hit a full percent. The survey found that 3 percent of those asked want someone else besides the listed candidates.

All of the named candidates except Biden have officially launched 2020 presidential campaigns. Biden is expected to make a decision soon, and those close to him say he is leaning towards running.

The survey was conducted from March 15 to March 17, has a margin of error of 5.4 percent, and surveyed 324 registered Democrats.

When the survey looks at voters in different age groups, it found Sanders has a massive lead with younger voters. Among those 18-29 years old, Sanders has the support of 61 percent while Warren is in second in that age group with just 15 percent. Among older voters, those over the age of 65, Biden wins out with 38 percent while Sanders is down at 26 percent in that age group.

“Unlike Michigan and South Carolina, where Biden competed with the youth vote, our poll shows that in Wisconsin, Sanders maintains the coalition he built in 2016 that earned him nearly 54% of the vote in the Democratic primary against Clinton,” Emerson Polling director Spencer Kimball said in a press release about the poll.

Biden getting in could be the only thing that could stop Sanders from banking the all-important Badger State early in the primary process. “If Joe Biden decides against running, it appears that this vote would split between Bernie Sanders at 23%, Beto O’Rourke at 20%, Kamala Harris at 16% and Elizabeth Warren at 14%. No other candidate receives over 10% if Biden does not run,” Emerson Polling explained in a post laying out where his support goes if Biden does not run. That means Sanders’ already formidable 39 percent would grow considerably without Biden in the race.

While Sanders is out in front in the primary, President Donald Trump looks very competitive in the general election. The only Democrat who does better than the margin of error in the poll against Trump in Wisconsin is Biden, who leads Trump in this survey by 8 percent, 54 percent for Biden to 46 percent for Trump. Trump is tied at 50 percent apiece in Wisconsin with Harris and Klobuchar, and O’Rourke only leads the president by 2 percent, 51 percent for O’Rourke to 49 percent for Trump. When polled against either Warren or Sanders, Trump trails by 4 percent with 48 percent in each case while both Sanders and Warren get 52 percent in that hypothetical matchup.

The general election survey was conducted on the same dates as the Democrat primary poll, with a broader 775 registered voters sample size and smaller 3.5 percent margin of error.

It is worth noting that there was not a single poll in the lead-up to the 2016 presidential election that showed President Trump beating former Secretary of State Hillary Rodham Clinton in the state of Wisconsin. In fact, the polling so predicted a Clinton victory that the RealClearPolitics average of polls in the lead-up to the 2016 election showed her ahead by 6.5 percent in Wisconsin. The last Emerson College poll that cycle, too, had Clinton up by 6 percent over Trump in Wisconsin, but Trump ended up defeating Clinton in the Badger State by 0.7 percent–or approximately 22,000 votes.

The 10 electoral votes that Wisconsin provides the general election winner are crucial to either side, and were critical to putting Trump over the top to win the White House against Clinton.