John McCain received a large endorsement Monday.
Former President George H. W. Bush announced he'll support Arizona senator in his run for the White House.
McCain is the clear Republican front-runner over challenger Mike Huckabee, although he has said he won't drop out.
As for the democrats, Hillary Clinton and Barack Obama are both stumping in the heartland today.
Voters in Wisconsin and Hawaii head to the polls Tuesday. Ohio and Texas hold their primaries March 4.