Answer:
The main reason for this conference was a growing threat that was rising after WW1 between certain countries especially in the Far East. WW1 didn't solve all the problems that arose, including this one and that is why United States decided to call up for a meeting between all great powers.
Step-by-step explanation:
Conference that lasted between 1921 and 1922 was held in the capital of United States.
Although WW1 ended three years earlier, certain questions were still opened.
Rise of totalitarian regimes, especially militarism in Japan was a big threat for worldwide peace, and that is why this conference was held, with a goal to reduce naval capacities of certain countries.