My Grandpa just turned 82 and served in both. He fought the Soviets in WWII (Finnish). Moved to the US and got drafted into the Army for Korea. Got out of the Army and was in the Air Force for the Cuban Missile Crisis (he was in Turkey) and Vietnam.
He has nothing but open contempt for communists, whatever they are calling themselves. I learned three things from him, botany, biology, and hunting.