As you say, worries that America is losing its edge in science and technology are overblown (“What Crisis?” June 14, 2008). The numbers you quote are persuasive enough: it accounts for 40 percent of total world spending on research and development; it produces 63 percent of the most frequently cited publications; it is home to 30 of the world’s leading 40 universities; it employs 70 percent of the world’s living Nobel laureates; and so forth. But there is a rub in your last paragraph, where you report that there is a worry in some quarters that as many as 41 percent of science and engineering doctorates are now in the hands of non-US citizens, a growing number of whom wish to remain in the country. The rub is in that very worry, innocuous as it may sound. If and when the American zealots manage to drive down the number of non-US citizens among the holders of science and engineering doctorates, all the jolly numbers quoted above are liable to follow suit, too. The zealots are prone to forget that the genius of America is in immigration, now as ever.