Funny that you should bring up the Constitution. I wonder what Mr. Jefferson, one of our Founders, was thinking when he sent warships to attack the Barbary pirates off of Tripoli for attacking our ships and hindering trade. Dude, you're beating the wrong drum. There are ample historic precendents to show that the Founders agreed completely with my view that our national interests are not limited by our borders. The fact that Libertarians have to reach outside the Founder's intentions shows how intellectually bankrupt and reactionary you are.
Let's say for the sake of argument that you're right. So what would you have done when Saudi Arabia and other Arab countries nationalized (stole) American companies' oil fields? Would you have gone to war against them?