Michigan State Police will switch back to garrison hats on Sunday, July 8, and away from the campaign-style hats troopers have worn since December 2016, the agency announced on social media. Garrison hats are what most people are accustomed to seeing Michigan State Police wear. MSP had brought the campaign-style hats, the original style worn by state troopers, on Dec. 22, 2016, in honor of their 100th anniversary. Troopers wore campaign hats from the founding of the Michigan State Police through the early 1920s. That decision was the result of a vote taken by State Police employees, said Lt. Mike Shaw, a Michigan State Police spokesman.