I think the one reliable pillar of a centrist foreign policy for the United States is to support democracy.
This means supporting democracy even when people we don't like get elected. Our long-term interests are best served by supporting democracy as a framework, which is the best help and hope we can give to the factions that will, when elected, support us.
This means we do not support dictators even if they are, temporarily, the enemies of our enemies.
This means we do not make war simply for our own economic interests. That is actually more craven than supporting dictators against other dictators. War for profit reaps us justified opposition all over the world.
This means we do not invade other countries on our own, ever. Sometimes armed intervention is necessary in an emergency to prevent genocide or repel aggression. That is what the UN or NATO or our other security alliances are for. When we invade on our own, colonialism follows almost every time.
And this means that sometimes we can't do enough to support democrats in other countries. There are limits to the power of even the world's greatest superpower. But we should keep pressing diplomatically for democracy in the most oppressive places.
Most of the world's people like the American people. They like our culture. If the doors were wide open, we would have 100 million immigrants, I expect, as fast as transport could be arranged.
When the United States supports democracy in their countries, we justify that good feeling and earn legitimate admiration. When we base our foreign policy on the realipolitik of the Great Game against this year's enemy, or, worse, on what is profitable to U.S.-based multinational corporations, we undermine that good feeling and destroy that admiration.
Finally, when we do support dictators, or do make war for profit, it comes back to bite us. Every time.