A striking but largely unnoticed feature of the controversy spurred by George W. Bush's aggressive use of signing statements is that Republicans, with only a brief interruption, controlled both houses of Congress from 2000 until 2006.1 The question of why a Republican President would use signing statements to slap down a Republican Congress did not meaningfully register in either a July 2006 American Bar Association (ABA) Task Force Report, a series of Boston Globe articles that won the Pulitzer Prize, or congressional hearings held by Republicans in June 2006 and Democrats in January 2007. 2 The subject of this controversy, instead, has been whether the President has a legal duty to enforce laws he thinks are unconstitutional and, relatedly, whether the President is improperly expanding his power by "quietly claim[ing] the authority to disobey more than  laws enacted since he took office."3
I do not doubt the appropriateness of journalists, academics, and lawmakers focusing their energies on the related questions of whether Presidents can disobey laws they sign and, even if they can, whether President Bush is nevertheless going too far in pushing his vision of presidential power. Those questions should be front and center in this conversation. At the same time, I think the question of how the President's use of signing statements might differ in periods of unified and divided government is worth examining.4
In this Essay, I will focus on the use of signing statements to advance the President' s policy agenda. My central claim is that Presidents have far stronger incentives to use signing statements to advance their agendas in periods of divided government. I am not arguing, however, that our system of checks and balances would be improved by increasing the use of signing statements during periods of divided government. Even though I will call attention to ways in which Presidents have advanced their political agendas through unilateral action, I do not take a position on the larger question of whether Presidents have too much or too Utile power vis-a-vis Congress.5 My argument is straightforward: when the President and Congress are of the same party, Presidents can advance their policy agendas by working informally with Congress and federal agencies. In periods of divided government, Presidents have less control of agency heads and less influence in Congress. Pre-enforcement directives - like signing statements - can be used to constrain agency discretion, signal Congress about presidential priorities, and - like other forms of unilateral presidential action - shift the burden to those who disapprove of presidential policies to override instructions to agency heads.
The fact that Presidents should make greater use of policy-based signing statements in periods of divided government does not mean that Presidents, in fact, have used signing statements for this purpose. Unlike executive orders, signing statements do not have much of a historical pedigree. Before Ronald Reagan sought to centralize presidential power through a host of 1 980s reforms, Presidents hardly ever attached a signing statement to legislation.6 More than that, even though Reagan's legal team saw signing statements as a useful mechanism for centralizing executive branch policy priorities,7 Reagan made only sporadic use of pre-enforcement signing statements. In short, because no President has systematically used signing statements to advance his policy agenda, there is little hard evidence to assess differences between policy-based signing statements in periods of unified and divided government.
In explaining why Presidents should see policy-driven signing statements as a useful mechanism to advance their agendas in periods of divided government, this Essay will proceed in two parts. Part I will detail why Presidents have incentives to pursue their policy agendas through unilateral action. Executive orders, unilateral presidential war-making, and structural initiatives that allow Presidents to centralize and coordinate agency policymaking are well documented examples of this phenomenon. …