The U.S hegemony means that U.S.A is the sole superpower. The U.S.A dominates the world in military, political, economic as well as cultural field.

Constraints on U.S Hegemony:

History tells us that empires declined because they decay from within. Similarly, the biggest constraint to American hegemony is from within broadly, there are three constraints on American power:

1. The first constraint is the institutional Architecture of the American state itself. American system is based on division of powers between the three organs of the government, i.e., legislature, executive and judiciary. These organs put many restrictions on military power.

2. The second constraint on the American power is the Open nature of the American society and the political culture.

3. The third constraint on the American power is the North Atlantic Treaty Organization (NATO).

Out of these three constraints, third constraint on American power is the most important in the future. NATO is the only organization in the world which can put some check on the American power. NATO will be successful in moderating the U.S hegemony.