I wouldn't pick on Canada too much, other than in jest. If we look at the tally, we've never had to give them foreign aid, rebuild their country after some hair-brained despot took them to ruination, or had to have weapons of mass destruction pointed at them (or at us). Most of the people are nice, even if they talk a little funny. Until the rag-heads got active, all you needed to cross the border was a smile. Actually, getting into Canada is still relatively easy. It's getting back into the USA's the problem. Now I lay my passport, military ID, driver's license out, and hang my FD badge/ID card from the mirror and hope the US Border Patrol doesn't want to see my hemorrhoid collection.
But I agree, cutting off foreign aid to a select group of s--thead despots for a few years would eliminate our debt in a hurry. It would also open them up to replacement similar to what happened in Egypt and Tunisia, and is going on in Libya and Syria. Who's going to prop them up? The Russians haven't got the money, the Chinese might but they're starting to sink under their own problems. Iran?? Even the Arabs don't want their money.
One of these years, we'll wake up and realize that the friends you have to buy are really not your friends.