America's attitude towards joining World War II before the attack on Pearl Harbor can be described as

Isolationist
Interventionist
Indifferent
None of the above

Isolationist

Explanation:

The US wanted to do what they could to stay out of the war as the economy within America had just started prospering again and many feared entering the war would put the country back into an economic depression. The US had been preparing and producing weapons for war just incase throughout the time the war had begun.