The correct answer is democratic US and communist Soviet Union competed to support and defend their political ideologies globally between 1945-1991
The cold war did not have any direct conflicts even though it was indeed close at certain points in time such as the Cuban Missile crisis. It didn't last three years and actually lasted for almost 50 years. There was a lot of hate going around but conflicts were only seen by proxy in other states that had civil wars or similar things.
