Answer:
The Europeans were interested in colonizing Southeast Asia for the same basic reasons that they wanted to colonize the other regions of the world. But with Southeast Asia, there was a new reason for wanting to colonize-- it was a backdoor to China.
Explanation:
<span>Prior to WW2, America had an isolationist foreign policy. It never joined the League of Nations, and staunchly avoided taking side with any colonialist power.
Anyway, America's priority at the time was to tackle the depression (which saw unemployment rose to 25%). On the whole the American population and their politicians were totally ignorant or blindsided to the frighten events in Germany and Japan, until it was too late for the countries invaded by the Axis aggressors.</span>
They wanted them to adapt Democracy. (Because the US was a democracy)