It clears up a lot of confusion when you understand that the US empire is not a national government which happens to run nonstop military operations, it's a nonstop military operation that happens to run a national government.

The wars are not designed to serve the interests of the United States, the United States is designed to serve the interests of the wars. The US as a country is just a source of funding, personnel, resources and diplomatic cover for a nonstop campaign to dominate the planet with mass military violence and the threat thereof. 

This campaign is not waged to benefit the American people or their security, but to benefit the loose international alliance of plutocrats and unelected empire managers whose wealth and power are premised on the world order of continuous violence, exploitation and extraction which the campaign of global domination upholds. This campaign of global domination and its manifestations as a whole may be referred to as the US empire, which has very little in common with the US as an individual nation.

Until you understand this, nothing the US government or the US war machine does will make sense. You won't understand why military operations are being waged which don't seem to benefit the American people in any way, and which if anything actually harm the national security interests of the United States. You won't understand why US foreign policy remains the same no matter who's in office, regardless of party or platform. You won't understand why the US and its allies do crazy things that otherwise make no sense for governments to do, like backing an increasingly unpopular genocide in Gaza, starting a cold war with China, or tempting nuclear armageddon with Russia.