Who was US president at the time of the Kent State Shooting?

After protesting students caused considerable damage to the city of Kent, Ohio national guard units were called out. They were hit by rocks, bottles and tear gas canisters by protesting college students, and, feeling their position in an open field vulnerable, and worried about snipers, they marched up Blanket Hill. Things got confusing after that, with an officer swinging his arm around suddenly, his service revolver in hand. Some guardsmen interpreted this as an order to fire, and a 13-second volley of rifle fire ensued, resulting in the deaths of four KSU students, and injuries to nine others.