The twin pillars of a sane foreign policy are:
(1) Building positive relationships, with an emphasis on free trade, and
(2) Avoiding negative relationships, with an emphasis on military non-intervention.
Armed Neutrality: The Swiss Model of Defense
Of course, it seems odd to describe the years since the start of the 21st century as a relatively peaceful time, but that is because, as Americans, we are living with a military-industrial complex whose financial future depends on keeping us as scared as possible for as long as possible. Our country, as a result, has been a laggard. And US attempts to choose winners and losers in other countries have been marked by repeated disasters: Osama bin Laden, Saddam Hussein, and Muammar Gaddafi all received military support from the US before they became US enemies.
The military budget of the United States, conservatively measured at around $700 billion (but probably closer to $1 trillion once all security measures and veteran benefits are considered), is approximately equal to all of the military budgets of all other countries combined. If the US military budget were cut in half, it would still be the largest in the world. Then, if it were cut in half again, it would STILL be the largest in the world. Then, if it were cut in half a third time, reduced to only one-eighth its current size, it would STILL be the largest in the world. And that's using the conservative measure.
Whatever motivates this enormous budget, it is certainly not for the defense of American soil. Indeed, when the Department of Homeland Security was created, this was a virtual admission that the Department of Defense had goals other than homeland security. No foreign army has the slightest capacity to invade the United States, and as North Korea has demonstrated, even the possession of a single nuclear weapon is enough to deter invasion.