To advance their policy agenda, presidents have two options. They can submit proposals to Congress and hope that its members faithfully shepherd bills into laws; or they can exercise their unilateral powers--issuing such directives as executive orders, executive agreements, proclamations, national security directives, or memoranda--and thereby create policies that assume the weight of law without the formal endorsement of a sitting Congress. To pursue a unilateral strategy, of course, presidents must be able to justify their actions on some blend of statutory, treaty, or constitutional powers; and when they cannot, their only recourse is legislation. But given the ambiguity of Article II powers and the massive corpus of law that presidents can draw upon, as well as the well-documented travails of the legislative process, the appeal of unilateral powers is readily apparent.
Not surprisingly, almost all the trend lines point upward. During the first 150 years of the nation's history, treaties (which require Senate ratification) regularly outnumbered executive agreements (which do not); but during the last 50 years, presidents have signed roughly ten executive agreements for every treaty that was submitted to Congress (Margolis 1986; Moe and Howell 1999b). With rising frequency, presidents are issuing national security directives (policies that are not even released for public review) to institute aspects of their policy agenda (Cooper 1997, 2002). Since Truman fatefully called the Korean War a "police action," modern presidents have launched literally hundreds of military actions without first securing a formal congressional authorization (Blechman and Kaplan 1978; Fisher 2004b). Though the total number of executive orders has declined, presidents issued almost four times as many "significant" orders in the second half of the twentieth century as they did in the first (Howell 2003, 83). Using executive orders, department orders, and reorganizations plans, presidents have unilaterally created a majority of the administrative agencies listed in the United States Government Manual (Howell and Lewis 2002; Lewis 2003). These policy mechanisms, what is more, hardly exhaust the options available to presidents, who regularly invent new ones or redefine old ones in order to suit their own strategic interests.
For years, political scientists paid precious little attention to these trends. Until recently, only one book had been written on the president's unilateral powers (Morgan 1970), and most journal articles on the topic were published in law reviews (see, e.g., Cash 1963; Fleishman and Aufses 1976; Hebe 1972). There are signs, though, that change is afoot. In the past several years, three books have focused exclusively on the president's unilateral powers (Cooper 2002; Howell 2005; Mayer 2001), and others are in the works. A number of articles on executive orders have been published in mainstream political science journals (Cooper 2001; Deering and Maltzman 1999; Howell and Lewis 2002; Krause and Cohen 1997, 2000; Mayer 1999; Mayer and Price 2002; Moe and Howell 1999a, 1999b). And for the first time, edited volumes on the general topic of the presidency are devoting full chapters to unilateral powers (Edwards 2005; Rockman and Waterman, forthcoming).
The nation's recent experience under the last two presidential administrations makes the subject all the more timely. From the creation of military tribunals to try suspected "enemy combatants" to tactical decisions made in ongoing conflicts in Afghanistan and Iraq to the freezing of financial assets in U.S. banks with links to bin Laden and other terrorist networks to the reorganization of intelligence gathering domestically and abroad, Bush has relied upon his unilateral powers in virtually all facets of his "war on terror." And to the considerable consternation of congressional Democrats, Bush has issued numerous rules that relax environmental and industry regulations concerning such issues as the amount of allowable diesel engine exhaust, the number of hours that truck drivers can remain on the road without resting, and the logging of federal forests. …