Read the full article by Mr. Romney in The Washington Post. I think it's pretty well written.

Some argue that the United States should simply withdraw its military strength from the world — get out of the Middle East, accept nuclear weapons in Iran and elsewhere, let China and Russia have their way with their neighbors and watch from the sidelines as jihadists storm on two or three continents. Do this, they contend, and the United States would be left alone. No, we would not. The history of the 20th century teaches that power-hungry tyrants ultimately feast on the appeasers — to use former Mississippi governor Haley Barbour’s phrase, we would be paying the cannibals to eat us last. And in the meantime, our economy would be devastated by the disruption of trade routes, the turmoil in global markets and the tumult of conflict across the world. Global peace and stability are very much in our immediate national interest.
http://www.washingtonpost.com/opinio...d02_story.html