Not sure, boatloads of money perhaps? And status as the global hegemon?

As vga1 says, a lot of American services are used by us. American goods too but not quite as much. When Trump complains about his trade balance he always ignores the revenue from services. The trade balance isn't actually bad when you include them.

But also influence through alliance. Even a superpower can't go it alone and use their military to bend others to its will.

You can't be serious.