MOI, the United States Constitution is quite clear. The U.S. military, lead by the president, is not be brought into war without a formal Declaration of War voted on in Congress. Just as the Constitution purposefully makes it difficult to pass laws, so does it make going to war purposefully difficult.
Now, it's been a long time since we've properly used the Constitution's rules to go to war, and look where it has brought us. The foreign policy we practice is dangerous to our national security, and we need to return to the limitations in the U.S. Constitution.
In 1953, the CIA staged a coup d'etat in Iran overthrowing a democratically-elected prime minister to install the Shah of Iran. The Shah was a ruthless leader with a secret police who would make anyone questioning the government disappear forever. This act conducted by the U.S. government radicalized the Iranian people who were very forward-thinking at the time we deposed their prime minister, and people usually don't forget that sort of thing. Now we have the U.S. government imposing, as it has on numerous occasions, economic sanctions on Iran including a blockade on all gasoline imported to Iran. This is crucial to the Iranian economy as they only have the oil-refining infrastructure to refine 50% of what their economy needs.
Finally, sanctions and other economic attacks on foreign nations only hurt the poor citizens as the ruling elite keep what they want leaving crumbs for the lower classes. These sanctions radicalize the citizens driving them into the arms of the ruling elite such as the mullahs of Iran. Iran was nearly at the point of revolution two years ago, but our sanctions have united the Iranian people with their government.
You want fewer enemies and more allies? Get out of those countries. That's not being isolationist; it's being non-interventionist. Either way, we can't afford it any more, and it will be a bad day when the U.S. has borrowed and printed its last dollar just to fire another missile in an undeclared war.