Back during the Cold War, we in America viewed the Soviet Union as an expansionist power, determined to bring Communist revolution to the rest of the world, by force if necessary. But we viewed ourselves as a defender of freedom and democracy--in short, we thought of ourselves as a conservative force.
This was nonsense. The United States is the most successful revolutionary power in the history of the world. We overthrew more regimes and wrought more massive social changes across the globe than the Soviets ever dreamed would be possible. But we mostly did it by example, not by force.
American diplomacy is at various times astute, innocuous, short-sighted, or just plain feckless. American military power also waxes and wanes, but for most of recent history even a weak American military is stronger than most of the rest of the world put together. But the most effective tool in the US foreign policy arsenal is soft power.
When you allow American goods and services, American business, and most of all American ideas into your country, your country is going to change. It's going to get more consumerist, which you will find very crass. It's going to get more morally diverse, which you will hate, at least to begin with. And it's going to get more democratic. If you're a dictator or a totalitarian regime or a theocracy, the worst thing you can do is engage with American interests, because your people are going to get impatient with you.
At the end of the Cold War, the strategy of spending the Soviet military into oblivion was well thought out, but the thing that ultimately did the Soviet Union in was when its citizens learned about American consumer culture and wanted it for themselves. The same thing happened in Southeast Asia, and China, and numerous South American countries. India's economy was radically restructured to enormous benefit when the Indian people understood what American-style consumerism could bring. Even nominally democratic countries in Western Europe became freer, more market-oriented, and more prosperous for embracing American ideas. Other countries think we're rude and unsophisticated, naive and arrogant. Maybe they're right. But they're missing the point: our secret sauce is so tasty that everybody eats it, even as they're complaining that it's just bland junk food.
Imagine America as an eager, happy, friendly puppy-dog. The puppy is kind of annoying, but most people love puppies. If you let the puppy jump into your lap, it's going to put its paws on your chest, it's going to get its face in your face, and it's going to lick you to DEATH. That's American soft power.
Of course, lots of people who like dogs don't want to deal with the mess that the puppy will make their your laps. But it's harder to refuse when the puppy's owner dotes over it and hands the puppy to you, all the while exclaiming how cute and cuddly it is. That's what American diplomacy is for.
And the American military? Oh, one final thing: The puppy is a Doberman Pinscher. It's very cute, but its mother is curled up on a doggy-bed about ten feet away. She's a very well-trained Doberman and will only react if you're mean to the puppy. If you toss the puppy out of your lap, the mother will growl. If you make the puppy yelp, the mother is likely to get up and nip you on the leg. But if you really hurt the puppy, the mother might just rip your throat out. Then the puppy will have to go play with your kids.
But it's a really, really cute puppy. Just let it lick you--you'll be friends for life!