One of the most enduring conceits of the modern era is that the Federal Reserve acts to goose growth and therefore employment while keeping inflation moderate (whatever that means--the definition is adjustable). This conceit is extremely handy as PR cover: the Fed really, really cares about little old us and expanding our ballooning wealth.
Nice, except it doesn't. The Fed's one real job is defending the U.S. dollar, which is the foundation of America's global hegemony a.k.a. The Empire.
One thing and one thing alone enables global dominance: being able to create "money" out of thin air and use that "money" to buy real stuff in the real world. The nations that can create "money" out of thin air and trade it for magnesium, oil, semiconductors, etc. have an unbeatable advantage over nations that must actually mine gold or make something of equal value to trade for essentials.
The trick is to maintain global confidence in one's currency. There is no one way to manage this, as confidence in a herd animal such as human beings is always contingent. Once the herd gets skittish, all bets are off.
The herd is exquisitely sensitive to movements on the edge of the herd, where threats arise. There are various tricks one can deploy to maintain confidence: pay a higher rate of interest on bonds denominated in one's currency, so global capital flows into your currency; treat this capital well with a transparent set of tax laws and judiciary / regulatory oversight, maintain a deep pool of liquidity so capital can enter and exit without stampeding the herd, and having at least a semi-productive, diverse economy that generates goods, services and income streams to support the currency.