WASHINGTON (AP) — Joe Biden has delivered decisive wins in Missouri and Mississippi, dealing an early blow to Bernie Sanders on a night when six states were up for grabs. Both men were focused intensely on Michigan, Tuesday’s biggest prize.

That’s where the Vermont senator scored an upset that lent much-needed credibility to his 2016 primary challenge of Hillary Clinton. It’s also where President Donald Trump’s victory four years was so narrow that Democrats are desperate to show they have the strength to flip it back.

Beyond Michigan, Sanders could get a boost in Idaho, North Dakota or Washington state. Polls there haven’t yet closed.