Actually they were sucking the UK & France dry of funds before they entered each World War and made New York the financial capital of the world a couple of decades earlier than would have been the case.
Ask your buddy if he knows where Canada was during the first two years of both WWI and WWII ... then ask him if he knows where the USA was during the first two years of both WWI and WWII.
Answer: Canada was fighting for freedom of others against real threats; the US was sitting it out because they didn't think they should be in a war that didn't directly effect the USA.