Joe Biden has won the state of Michigan, a key swing state in the race for the presidency, AP projects.Why it matters: Biden’s flip of the state’s 16 electoral votes comes after a similar victory in Wisconsin — and bodes well for the former vice president’s prospects in the outstanding Rust Belt battleground of Pennsylvania.With swing states North Carolina, Nevada, Georgia and Pennsylvania still outstanding, Biden only needs six more electoral votes in order to clinch the presidency, according to AP's projections.Biden was leading in the state by 8 points the day before Election Day, according to FiveThirtyEight's average of polls.What to watch: Incumbent Sen. Gary Peters (D) is facing a re-election battle against Republican challenger John James in Michigan, one of the races that could determine control of the Senate.