"In this world, there are only two tragedies," Oscar Wilde once wrote. "One is not getting what one wants, and the other is getting it." As the U.S. Federal Reserve inches closer to achieving its targets for the domestic economy, it faces growing pressure to normalize monetary policy. But the domestic economy is no longer the Fed's sole consideration in policymaking. On the contrary, America's monetary authority has all but explicitly recognized a new mandate: promoting global financial stability.

The U.S. Congress created the Fed in 1913 as an independent agency removed from partisan politics, tasked with ensuring domestic price stability and maximizing domestic employment. Its role has expanded over time, and the Fed, along with many of its developed-country counterparts, has engaged in increasingly unconventional monetary policy — quantitative easing, credit easing, forward guidance, and so on — since the 2008 global financial crisis.

Now, the unconventional has become conventional. A generation of global market participants knows only a world of low (or even negative) interest rates and artificially inflated asset prices.