WASHINGTON — As the growth of the United States economy outstrips the rest of the developed world, American policy makers are allowing Europe, Japan and even China to seek a little more prosperity — at the expense of Americans.

The Obama administration and the Federal Reserve have watched quietly in recent years as foreign governments and central banks have chipped away at the dollar value of their currencies, strengthening their export industries in the hope of stimulating their economies.

The trend is likely to intensify over the next year as the Fed retreats from its own stimulus campaign while the European Central Bank and the Bank of Japan expand their efforts. Mario Draghi, the head of the European Central Bank, said on Thursday that it would begin a new round of bond purchases this month.

The United States has long argued that markets should determine the value of currencies and criticized nations that try to manipulate exchange rates. The current silence reflects both the simple reality that the American economy needs less help than the rest of the developed world and the judgment of officials that the United States would benefit greatly from stronger global growth. That, they say, would be true even if, in the short term, it makes the country’s goods a little harder to sell and jobs a little harder to find.