American military spending is larger than that of the next 12 countries put together. That's a *lot* of military spending.
In traditional terms, it would be a fine way to project power across the world...except...
Guerrilla warfare is the art of a smaller, much weaker force, using hit-and-run and disinformation tactics to defeat a much larger force.
Take a look at what is happening with the American government right now...Trump riled people up and was voted in to theoretically take on "the establishment" and "drain the swamp". He ran as a Republican (though threatening to be an independent at times). His election was so fraught and aggressive that the Republicans were in doubt if the party were going to survive the election.
When he got to office, he identified the Democrats as his enemies, and immediately alienated them, making it impossible to work with them.
The anger and intrigue surrounding the election, and his non-unifying approach to the Democrats made them his enemies, and guaranteed that he'd have a tough time getting his appointees through. Then he chose the worst of a lot of bad apples to be his toadies, further guaranteeing opposition to his efforts.
Then he backed and pushed very hard on AHCA, which would have hurt a great many people. It was so bad, the Republican party fractured, and a significant portion of them had to fight the bill. Republicans have had 7 years to agree on what to do...this wasn't a rush job. When push came to shove, they made it impossible for Trump to get his bill through.
Again, instead of trying to work with folks in Congress to change the bill into something useful, he has told them, "See you in the 2018 elections". In other words, he's going to campaign to get more people in congress who will obey him blindly, no matter how much damage he's going to do to America as a whole and Americans individually.
Of course, his trips to play golf have taken up literally 1/3 of his time in the office, so he hasn't had a chance to appoint many of the people needed to run the government.
Result? The US government is on auto-pilot, without a credible leader. It's weakened, and brittle.
That's how you fight the US, apparently: by making it fight itself.