You're not very familiar with American history.
And we keep military forces overseas in order to stop attacks from coming to us on our own soil (and while we're at it, to defend allies). Every conservative American knows that.
I don't know what you mean by a 'conservative American', but I know what an empire is. When you have over quarter million men under arms propping up 'friendly' governments around the world you're running an empire. Don't be squeamish about it. Playing kingmaker over the lines drawn by the last gasps of the French and British empires in the Middle East has us embroiled in a war today.
You can make the argument that we should have an empire instead of a neutral, free republic, but don't pretend it's what our Founders set out to create. Not on this day.