In an online article on Al Jazzera, the United States is said to be worried about the build-up of the Chinese military. The same report highlights military expenditures of some major powers. The numbers speak for themselves and someone has to take the first steps in backing away from a future catastrophic confrontation. It must be the US.
Spending as a proportion of global total (2005 figures):
Source: Stockhom International Peace Research Inst. (www.sipri.org)