The dramatic and unpredictable US presidential election will take another turn tomorrow when voters in Michigan and Mississippi cast their ballots in primary contests.

Donald Trump is leading the polls in Michigan Republican primary - a state that has been won by Democrats - but narrowly so - in the past few elections. And his supporters may go beyond those who traditionally vote Republican.

The BBC's Rajini Vaidyanathan went to Michigan to find out what's driving his support in the state - including a union member who is backing Trump despite concerns about some of his positions.

Rich Ashby of Newport, Michigan, says that even though some of what Donald Trump says makes him a risk, America "was built on risk".

Filmed by Ian Druce. Edited by Bill McKenna. Produced by Mat Morrison.