Former Vice President Joe Biden has all the momentum going into the next round of primary contests, which could help him gain an insurmountable delegate lead in the race for the Democratic presidential nomination.

On Tuesday, voters head to the polls in Idaho, Michigan, Mississippi, Missouri, North Dakota and Washington state. Biden is expected to do well in most of those contests based on the strength he demonstrated on Super Tuesday with moderates, Black voters across the South and rural voters in the Midwest.

The most favorable ground for Sen. Bernie Sanders (I-Vt.), who currently trails Biden in delegates, lies in Michigan and Washington. The Vermont senator upset Hillary Clinton in the Great Lakes State in the 2016 Democratic primary, so he’s a known commodity there. His economic and trade message is also likely to resonate in Michigan, as it has in other Rust Belt states. That’s why his campaign this week canceled a scheduled appearance in Mississippi and added more stops to his Michigan itinerary.

But Biden could also win a number of delegates in Michigan, if not the state overall. His campaign this week rolled out a slate of endorsements from top Michigan Democrats, including from Gov. Gretchen Whitmer and Rep. Elissa Slotkin, the freshman lawmaker who flipped a suburban GOP district in 2018.

“In Michigan, we have a rich tradition of hard work, decency, and passionate pragmatism. That is what is expected of us in our lives, and that is what I believe we need from our elected leaders. That is why I support Joe Biden,” Slotkin said in a statement.

The map looks even more daunting for Sanders later this month when voters in Arizona, Florida, Illinois, Ohio (on March 17) and then Georgia (on March 24) head to the polls. Many of the same dynamics apply in these states ― Sanders is considered competitive in the Midwestern contests, but he faces extremely difficult odds in the South. In Florida, for example, where 219 pledged delegates are up for grabs, Biden leads Sanders 61% to 12%, according to a recent poll. And that was before Biden’s surge on Super Tuesday and before former New York City Mayor Mike Bloomberg dropped out of the race.

“Folks...barring a seismic event, this race is pretty much over,” Dave Wasserman, editor of the nonpartisan Cook Political Report, tweeted in response to the Florida poll in particular.

The brightest spots for Sanders looking forward include Wisconsin, which votes on April 7, and the “Acela primary” states across the Northeast ― New York, Pennsylvania, Connecticut, Delaware, etc. ― that vote on April 28. But those are over a month away, and it’s difficult to see the senator making up the difference then if Biden performs this month as well as he did on Super Tuesday.

Talking to MSNBC’s Rachel Maddow on Wednesday, Sanders vowed to drop out of the presidential race if Biden ends up with a plurality of pledged delegates heading into the Democratic convention in July.

“If Biden walks into the convention, or at the end of the process, [and] has more votes than me, he’s the winner,” Sanders said.