Richard III
Duke of Gloucester
1. Yup, about 1812, as I said, I didn't think it was the main reason either. I would say that British impressment of sailors and the blockade were more important causes of the war, but a crucial factor was the desire for conquest. I can say that with some confidence because there is a measuring stick: senate votes in favour of war. The decisive margin was provided by the Western states, who specifically argued for expansion as a benefit of war with Britain.
2. The odd thing is, until they hit the prairies, the Americans DID treat the Native Americans like nations - they just treated them particularly badly (something like the way Germany treated Poland as a nation, but I digress - and note that Canada often did the same). Treaties with native nations were common, and the various native nations in the east were fairly sedentary.
3. By way of an answer on the border dispute, I should note that it took about forty years for Canada to sort out its border with the US after Confederation. Russia and China still can't agree on their borders along the Amur over a century after those borders were fixed. Mexico and Texas never figured it out because it didn't really matter enough to either until the border became an American border instead of a Texan one.
In short, I don't think empire building was a founding tradition of the US, but it was a tradition. Fair to say it ended between 1919-1945. At least, I'd say that. Others on this forum would beleive that September 11th was a ploy to add Afghanistan as the 51st state, but....
But if I actually had to pick it would be Truman or Washington.
The cause for the economic growth of the last decade was unprecidented gains in productivity 3.0%+ yearly, not slick willie's economic policy (or lack there of).
