Reasonable people can disagree about this, but I would maintain that there are two strains of neoconservative thought. The first is that American security ultimately depends on the continuing existence of like-minded democratic regimes throughout the world, so we should be prepared to impose liberal democracy on other countries by force, if necessary. That approach, unsurprisingly, failed miserably in Iraq, and thus is rarely heard today.
The second requires us to be the world’s policeman–not its savior. Its proponents argue that, in a world that has become effectively much smaller as the result of technological change, small brush fires can become infernos endangering our security almost overnight. Minor civil wars in faraway lands of which we know little, for example, can result in waves of refugees and terrorism affecting the entire world. It’s ultimately cheaper and less risky to deal with these problems at their source than at home. The US is the only power strong enough to do that. If the rest of the world benefits from that level of American engagement, so be it.
#2 makes sense, but is it sustainable if we are going into a period of relative decline? More on that later in the week.