DETROIT — Former President Donald Trump is scheduled to return to Michigan Saturday with Republicans in the state hoping he can motivate his base of supporters and help secure Macomb County, a key area the GOP needs to win in November. Trump will speak at 7 p.m. Saturday night at the Macomb County Community College Sports and Expo Center in Warren. It will be his first rally in Michigan since April 2 and will take place 38 days before the Nov. 8 election. The event will be helpful to GOP candidates because Trump has a unique ability to activate a segment of the state’s electorate, argued Jamie…