Number 67 in the ‘top science stories of the year’ in Discover Magazine is entitled ‘U.S. Science Supremacy Threatened by Competition’. Some interesting facts: according to the National Science Board, an independent policy group that advises the president and the congress,

the drop in foreign applications – down 28 percent at the graduate level – is (…) certain to affect the future of science. Many who come here to study do not return to their native countries. A survey by the National Science Foundation in 2000 reported that 38 percent of U.S. scientists with doctorates were born abroad.

Also:

the number of research articles by Americans has been stagnant compared with an increasing number written by Western Europeans in the last decade.