Answer: An Isolationist; a person favoring a policy of remaining apart from the affairs or interests of other groups, especially the political affairs of other countries.
An Interventionist; favoring intervention, especially by a government in its domestic economy or by one country in the affairs of another.
So, if i lived in the 1930's i would be an Interventionist.
Question: Would you have thought it would be a mistake for the US to get involved in another European conflict or would you have argued a threat to freedom anywhere is a threat to freedom everywhere?
Answer: Well considering every conflict we have been is has led us to better lives in the end, no i don't believe it was a mistake.