Four years ago, Sanders scored a massive upset in Michigan, narrowly winning despite trailing by more than 21 percentage points in the RealClearPolitics polling average on the eve of the 2016 primary. Michigan stands as one of the most significant polling failures in modern politics.

This time, Sanders needs a repeat — and then some. Biden’s average lead in the state was a staggering 29 points prior to the Monmouth poll’s publication, according to RealClearPolitics.

The Monmouth survey, which was conducted March 5-8, shows Biden winning across many demographic groups, particularly women, older voters and non-whites. Biden leads Sanders among women by 20 points, and among men by 10 points. Biden leads by 10 points among white voters, with voters of other races giving Biden a 17-point lead. (The survey did not break out the results for specific, non-white races.)

Among voters under age 50, Sanders has an 11-point lead, 49 percent to 38 percent — smaller than his advantage among young voters in previous states. But Biden leads by 32 points among voters aged 50-64, and he leads by 46 points among voters 65 and older.

“Biden appears to have the advantage because he is doing well among some groups that Sanders won four years ago. But as we learned in 2016, Michigan can defy expectations,” said Patrick Murray, director of the Monmouth University Polling Institute. Monmouth’s final Michigan poll in 2016 showed Hillary Clinton leading Sanders by a similar margin: 13 points.

The Detroit Free Press poll, conducted March 4-6 by in-state pollster EPIC-MRA, gives Biden an even larger, 24-point lead — almost identical to Clinton’s 25-point lead in their final survey four years ago. But EPIC-MRA pollster Bernie Porn says he’s confident in the numbers.

“If anything, it may be low in terms of the percentage that Biden may get,” Porn told the Free Press.

Mitchell’s final poll in 2016 showed Clinton 27 points ahead of Sanders. Just as in 2016, the firm’s latest survey did not contact voters without landline phones. According to 2018 data from the National Center for Health Statistics, 57 percent of adults in Michigan live in households with only a mobile phone and not a landline.

Steve Mitchell, who has worked mostly for Republican political candidates, said he feels “very confident” in the results of Sunday’s survey, despite the lack of cell phones and Sanders’ upset victory in 2016.

“Four years ago, there had not been a presidential primary of any importance in years and years. And so therefore we really did not know how to develop the sample,” said Mitchell.

Mitchell’s final poll in 2016 was modeled after state primaries for other, downballot offices in August of election years. Sanders’ base of young voters disrupted that.

“You had a huge number of young people voting. We weren’t polling them, and by a two-to-one margin they were voting for Sanders,” Mitchell said.

Even if young voters come out to back Sanders in large numbers, pollsters are ready, Mitchell said.

“We know what the turnout is going to be,” he said.

The Monmouth University poll surveyed 411 likely Democratic primary voters — with the majority on cell phones — and has a margin of error of plus or minus 4.8 percentage points.

The Detroit Free Press poll surveyed 400 likely primary voters, half on cell phones, with a margin of error of plus or minus 4.9 percentage points. And the Mitchell Research poll surveyed 602 likely primary voters only on landlines, with a margin of error of plus or minus 4 percentage points.