There are several examples of “proxy wars” in history between Russia (Soviet Union) and the United States. This is something to keep in mind as we watch events unfold in the Ukraine.
These were wars where the U.S. and Russia did not go “head to head” against each other, but rather, they supported another country in a war against the other.
For example, in the Soviet-Afghan war, the U.S. and other nations supported the Seven Party Mujahideen Alliance (or the “Peshawar Seven”) with weapons and money (reportedly in the billions of dollars) in order to help them fight the Soviet-led Afghan forces.
In the Vietnam War, the North Vietnamese, the National Liberation Front and its military arm, the Viet Cong, received support from the Soviet Union and China. According to some analysts, by the late 1960s more than three-quarters of the military and technical equipment received by North Vietnam was coming from the USSR.
In the Korean War, the Soviet Union provided material aid to both the North Korean and Chinese armies. They provided weapons (including planes), medical services, and Soviet pilots to aid their fight against the United States.