has US troops marched fought against American citizens inside the USA? Off hand, I can think of the Veteran's March against Washington and Kent State. Any others? For those who have forgotten MacArthur's role, http://en.wikipedia.org/wiki/Bonus_Army Many of the war veterans had been out of work since the beginning of the Great Depression. The World War Adjusted Compensation Act of 1924 had awarded them bonuses in the form of certificates they could not redeem until 1945. Each service certificate, issued to a qualified veteran soldier, bore a face value equal to the soldier's promised payment plus compound interest. The principal demand of the Bonus Army was the immediate cash payment of their certificates. Retired Marine Corps Major General Smedley Butler, one of the most popular military figures of the time, visited their camp to back the effort and encourage them. On July 28, U.S. Attorney General William D. Mitchell ordered the veterans removed from all government property. Washington police met with resistance, shots were fired and two veterans were wounded and later died. President Herbert Hoover then ordered the army to clear the veterans' campsite. Army Chief of Staff General Douglas MacArthur commanded the infantry and cavalry supported by six tanks. The Bonus Army marchers with their wives and children were driven out, and their shelters and belongings burned.