In the American Political Science Review, Dan Nexon and Thomas Wright on what hinges on the answer to “Is there is an American Empire?”:
In informal empires the lines between influence and rule necessarily blur. When actors believe that certain options are “off the table” because of an asymmetric (if tacit) contract, or consistently comply with the wishes of another because they recognize steep costs from noncompliance, then the relationship between the two becomes effectively one between ruler and ruled (Barnett and Duvall 2005, 63). Recall that one of the fundamental processes of imperial rule involves the ongoing negotiation of contractual bargains between a variety of actors. Intermediaries and local actors may, in theory, opt to reject or renegotiate any aspect of the imperial bargain. They may decide not to because they accept the legitimacy of the bargain, out of habit, or because they fear imperial sanction. The fact that such sanctions may involve the loss of crucial military, economic, or political support rather than the use of force does not render the relationship nonimperial (Barkawi and Laffey 1999).
These considerations shed important light on the salience of imperial structures and dynamics in American foreign relations. The American-led invasion of Iraq, for instance, currently positions the United States in an imperial relationship with that country. The United States negotiates and renegotiates asymmetric contracts with other states—–such as its bargains with Pakistan concerning counterterrorism policy—–that place foreign leaders in the structural location of local intermediaries between U.S. demands and their own domestic constituencies (e.g., Lieven 2002). Its basing agreements incorporate many of the hallmarks of imperial bargains (Johnson 2000). But “American empire” is not a phenomenon restricted to the post-Cold War or post-9/11 world. Most of the architecture of contemporary imperial relations in American foreign policy developed during the Cold War (e.g., Bacevich 2002). Decades-long geopolitical developments have, in fact, tended to render American relations less, rather than more, imperial in character.