About a decade ago I asked a (very) senior economic policymaker what he worried about in private. The dollar, he replied. If the U.S. didn't deal with its spiraling deficits, foreign investors would eventually lose confidence in the greenback, and all sorts of nasty things would ensue: a financial crisis, a big rise in interest rates, a recession, and a lasting blow to American living standards. Well, we got the financial crisis and the recession, but the dollar has done fine. If anything, the past few years have seen a strengthening in the dollar's role as the global reserve currency. Talk of the renminbi, or even Bitcoin, taking its place is just talk. During the recent selloff in emerging markets, where did global investors and foreign central banks park their money? At the U.S. Treasury. In late January, as investors fled Turkey, Brazil, and other places, the yield on 10-year Treasuries fell back to 2.75%.