"The Americans have brought their armed forces back home, adopted sensible foreign and domestic policies, and are starting to see eye-to-eye with people whom they once found too foreign to relate to. Now is the perfect time to strike!"

Our global hegemony ensures stability of trade for the entire world, and that stability is the reason that other countries eagerly trade and generally deal business with the US. Unfortunately, if we back away from our role as world police, the resulting power vacuum will see some other country take up the role at best, and at worst we could see another large scale conflict as emerging powers compete for dominance.

Our current foreign policy is far from ideal, but there is a delicate global balance which would be dangerously upset if we ceased global operations and "world policing." The GP is niave to think that such rosy, utopian intentions would not be taken advantage of by other global players. Look, for instance, at the current posturing by China in the Pacific. Imagine the scaling of their operations if there was no one in our position to apply pressure against them.

Someday, sure. But, globally, humans are still viciously tribal, and some form of enforcement keeps everything running smoothly for everyone. And while Americans foot much of the bill, there is no denying that our benefit is of larger proportion as well.

I feel like a lot of people have a lot of trouble appreciating the wars that _didn't_ happen under American hegemony. I don't believe we're perfect in anyway, but under our influence the world has been more peaceful and interconnected than at any other time in world history.

Similar to the violence that was quelled under Saddam. It's difficult to appreciate and measure that which is absent.

Rephrase that last sentence a few different ways and you'll see the problem:

"Now is the perfect time to close the Suez Canal" "Now is the perfect time to invade South Korea" "Now is the perfect time to plunder any ship with cargo" "Now is the perfect time to take Qatar"

The reality is, America's military presence abroad is a stabilising force. Take that away and other powers will move in to fill the vacuum.

Please elaborate how exactly this leads to weakness? And how do you define it in the first place?

power and political vacuums tend to want to be filled