The I.M.F. revised its World Economic Outlook on Tuesday, and compared with its forecasts from July, it now expects 2014 economic growth to be 0.5 percentage points stronger in the United States and 0.3 percentage points weaker in the countries using the euro (with particularly weak projections in the core of Europe, namely Germany, France and Italy).

It is true that the Federal Reserve finally has its sights on ending its long campaign to push down American interest rates, even as the European Central Bank and others overseas redouble their efforts. But the central banks are in many ways the cart, and the underlying economic performance of the two sides of the Atlantic is the horse.

The Fed is now poised to start removing its easy money policies precisely because they have worked and helped spark stronger growth. The European Central Bank is now having to consider more radical action because its earlier reluctance to intervene has led the European economy to a bad place, that and deep-seated imbalances in the European economy.

The mantra of the global finance ministers and central bankers over the last year has been that countries must pursue a mix of policies that will ensure stable growth and stable prices in their countries — “domestic tools for domestic purposes,” as Mr. Lew put it Tuesday — and that exchange rates can then settle where they may.

Financial policy makers have generally abided by this. Even when taking actions that are sure to drive down their currencies, they have usually framed it as being focused on domestic purposes. (The exception has been some recent rumblings from Mr. Draghi about pushing down the euro, though that may be because in export-centric, inflation-phobic Germany, it goes over far better to say “we need cheaper money to make the currency more competitive” than “we need cheaper money to increase inflation.”)

That helps explain why the Americans are taking the rising dollar in stride. Even as officials will surely start to get an earful from American exporters, they can take solace in the fact that the rally is being driven by a long-awaited pickup in domestic economic activity. And the United States, they are concluding, has more to gain from Europe and Japan getting their policies right and getting their economies on track than it has to lose from American companies facing a less advantageous exchange rate for the time being.