Foreign Affairs has a fascinating look at America's ascendancy to nuclear primacy since the fall of the Soviet Union.
Today, for the first time in almost 50 years, the United States stands on the verge of attaining nuclear primacy. It will probably soon be possible for the United States to destroy the long-range nuclear arsenals of Russia or China with a first strike. This dramatic shift in the nuclear balance of power stems from a series of improvements in the United States' nuclear systems, the precipitous decline of Russia's arsenal, and the glacial pace of modernization of China's nuclear forces. Unless Washington's policies change or Moscow and Beijing take steps to increase the size and readiness of their forces, Russia and China -- and the rest of the world -- will live in the shadow of U.S. nuclear primacy for many years to come.
Personally I think it's good for America to be stronger than anyone else in the world, but the article examines both the positive and potential negative outcomes.