From Jim Talent writing  Sowing the Wind at National Review Online:

A great nation with neither power nor strategic purpose is just as vulnerable, and perhaps more so, than a small nation. Great nations have targets on their backs. They can never hunker down and expect the winds of conflict to blow over them. The United States has more friends and partners than most great nations have historically had, but America also has adversaries. Those adversaries – subnational movements like al-Qaeda and its associates, rogue regimes like North Korea and Iran, and authoritarian governments like Russia and China — understand clearly that America is the obstacle to achieving what they have defined as their national interests. They chafe under the restraints of the norm-based international system, which the United States midwifed during the Cold War years, and they know that if they can defeat America, the system will go down with it.