Joe Biden decisively won Michigan's Democratic primary on Tuesday [US time], seizing a key battleground state that helped propel Bernie Sanders' insurgent candidacy four years ago.

The former vice president's victory there, as well as in Missouri and Mississippi, dealt a serious blow to Sanders and substantially widened Biden's path to the nomination. The Vermont senator's hopes rested on Idaho, North Dakota and Washington, where votes were still being cast or tabulated but where far fewer delegates were at stake. Biden again showed strength with working-class voters and African Americans, who are vital to winning the Democratic nomination.