When you have a number of choices to select from, use a list or a chart. Draw a circle or a semi-circle with a radius of about 4 - 6. Mark the choices off as degrees on the circle. Hold the pendulum in the center and the swing of the pendulum will line-up with the appropriate marked off selection.
April 24, 1965 - President Johnson announces Americans in Vietnam are eligible for combat pay. May 3, 1965 - The first U.S. Army combat troops, 3500 men of the 173rd Airborne Brigade, arrive in Vietnam.
Three days later Germany declared war on the US, followed by Italy. Democrat Truman sent US troops into Korea after the North Koreans invaded South Korea, but again, officially this was not a war but a police action under UN auspices. Republican Eisenhower sent the first US troops to South Vietnam.