Could world leaders have prevented World War II from
happening Support you answer fully.

Yes, they could have but it would have been very difficult.

Explanation:

The reason is that the attitudes of the leaders of Nazi Germany and Imperial Japan (Hitler, and Hirohito, respectively) were very pro-war. Both leaders were pursuing an aggressive expansionary policy, whcih means that they wanted to conquer a lot of new land in order to be colonized by German or Japanese people respectively.

However, some of the policies of the British, French, and American government could have been different. For example, the could have been harder on Hitler at first, when he was pursuing the annexation of Austria, and Czechia.