U.S. Senators Gary Peters (D-MI) and Joni Ernst (R-IA), joined thousands of veterans to observe Memorial Day at the annual Rolling Thunder First Amendment Demonstration Run. The motorcycle ride brings together over one million riders and spectators combined to honor service members killed in action (KIA), those still missing in action (MIA) and prisoners of war (POW). The two are co-chairs of the bipartisan Senate Motorcycle Caucus and both former service members. Peters is a former Lt. Commander in the U.S. Navy Reserve.

Rolling Thunder began in 1988 as a response to the Vietnam War era. Led by Vietnam veteran Ray Manzo (CPL, USMC), a group of veterans organized the first run to raise awareness of the significant numbers of American service members missing in action or left behind as prisoners of war. According to the Defense POW/MIA Accounting Agency (DPAA), there are more than 82,000 Americans still missing from WWII, the Korean War, the Vietnam War, the Cold War, and the most recently concluded Gulf Wars.

Longtime motorcyclists, Peters and Ernst launched the bipartisan Senate Motorcycle Caucus in 2017 to facilitate discussions on a range of issues on behalf of both motorcycle riders and manufacturers.