Are you a domestic terrorist?

[Jester]

Right and the Hapsburg Empire didn't extend into Mexico either.

I'm not sure what you mean. By the time Mexico went to war with the USA, it was an independent nation, and had been for almost thirty years.

I recall the US purchased most of North America from France, and wrested or purchased the remainder from either Spain, or the British.

About a third was bought - the Louisiana purchase - not that the French had any particularly great claim over the area, which was by and large inhabited by indigenous peoples. The rest was "wrested" or "purchased" in peace treaties, mostly at the ends of wars that the US won.*

http://en.wikipedia.org/wiki/Monroe_Doctrine
The intention was to push Europe out of colonialism, rather than to practice it ourselves. Oh, well, you know what they say about good intentions.

Indeed. I think you'll find all colonial powers had some similar justifying doctrine which served the underlying purpose - the acquisition of colonies. The British had very high minded ideas about good government and civilization in India, and that the Spanish really did think they were bringing God to a land plagued by the devil's work. Or, at least, they told themselves these pious untruths, a kind of colonist's foma. But when it came down to brass tacks, it all amounted to roughly the same deal - you do what we tell you to, because we have bigger and better guns.

-Jester

*edited to "mostly", since the Oregon territory, while acquired in part from threat of war, was obtained through treaty without war.