Several of Donald Trump's rivals stepped up their attacks against him in Wednesday's second Republican presidential debate, urgently trying to dent the former president's commanding primary lead.Trump went to Michigan, aiming to capitalise on the autoworkers' strike in a key state that could help decide the general election.

Several of Donald Trump's rivals stepped up their attacks against him in Wednesday's second Republican presidential debate, urgently trying to dent the former president's commanding primary lead.Trump went to Michigan, aiming to capitalise on the autoworkers' strike in a key state that could help decide the general election.