Question

What 1968 event caused u.s. military leaders to be concerned that a quick end to the war was not possible?

Answer 1

The U.S. military suffered a major strategic blow in the Tet Offensive... hope it helps

Answer 2

The military leaders are concerned that a quick end to the war is not possible, because the US military suffered a major strategic blow in the Tet offensive. This offensive was a military operation organized by North Vietnam and carried out by the army of Vietnam of North and Vietcong in 1968 against the Allied forces led by the United States.