Communism power became to decline!
The action FDR want congress to take is shown on this image
Either communist oppression or Germany's strength. I'm not sure.
Answer:
The Mexican-American War, waged between the United States and Mexico from 1846 to 1848, helped to fulfill America's "manifest destiny" to expand its territory across the entire North American continent.
Explanation:
https://www.history.com/topics/mexican-american-war