Six states are holding Democratic primaries or caucuses on Tuesday: Idaho, Michigan, Mississippi, Missouri, North Dakota and Washington, worth a collective 352 delegates to the Democratic National Convention.

There have been no recent polls by reputable organizations in North Dakota. Here is what the polls say about the other five states.

Michigan

Michigan, which will award 125 delegates, is the biggest prize this week — and a crucial one for Senator Bernie Sanders of Vermont, who has effectively ceded large parts of the South to former Vice President Joseph R. Biden Jr. in order to go all-in on the Midwest.

It is worth noting that polls were very wrong in Michigan in 2016: They showed Hillary Clinton with a large lead, but Mr. Sanders ended up eking out a victory.