Increasing US credibility decreases allies’ defense expenditure

Increasing US credibility decreases allies’ defense expenditure

There are fine lines to be walked here. The United States has alliances for the most basic purpose of augmenting its power, its reach and the totality of its presence. From this perspective, it is in Washington’s interests to have militarily proficient friends. But its alliances have other rationales that cut against that simple desire. Another central historical purpose of American alliances in the postwar period is to contain its allies. By providing security, Washington in theory removes incentives for its allies to rearm and reassert themselves as challengers. This imperative, to depress allies’ defense expenditure, requires in turn that Washington must establish a reputation for being a reliable security provider. Failure to maintain that baseline of confidence could lead the client to pursue belligerent self-help, or even other allies in lieu of the United States. Yet, establishing a reputation for reliable security provision can and does have a perverse result—it creates a moral hazard. Allies’ confidence in American backing can embolden them to behave recklessly in ways that Washington dislikes. Conversely, the dependency Washington forms on the alliance, as an indispensable platform for its power projection, creates reverse leverage, making Washington reluctant to attempt to impose itself with threats of abandonment or even public criticism.