Question

What connection did the Monroe Doctorine and the Roosevelt Corollary have in particular?

Answer 1

Monroe doctrine was a policy that basically said "Keep out of the Americas Europe, or else". The corollary was an addition to the Monroe doctrine which allowed the US to intervene in Central America to stabilize economies when they couldn't pay off international debts.

Answer 2

It also spurned the SpanAm War, whereas the US could declare war on European invaders. It would be cited as a cause for war in WWI, II, and even today's War on Terror in the Middle East. However, following WWII the Monroe Doctrine was basically forgotten, as we have been at war abroad in some area since then.

The Monroe Doctrine was America's foremost document that called for isolationism, an idea that ran strong largely til the late 19th to early 20th Century when we began to intervene in foreign military affairs.