Over the past two decades, scholars of the American presidency have emphasized executive unilateralism. Natural enough, perhaps, given today's headlines – but the landmark books on executive orders (EOs) that started to appear around 2001 were meant as a corrective to a sense that the subfield had too often, and too anecdotally, centered on Presidents’ skills and personality as their source of power. If the diagnosis was sometimes overstated, the systematic study of Presidents’ formal and institutional authority was still an important remedy.

Early on, this research tended to focus on the causes, or at least the correlations, linked to EOs’ issuance; their purpose and contents were at first of less concern, not least because they were harder to quantify. But orders vary widely in their substantive importance. Thus a President issuing forty orders was not obviously twice as unilateral (or tyrannical, as critics would have it) as a President issuing twenty. Further, executive orders themselves were not the only tool Presidents had for unilateral action – a wide variety of directives, from proclamations to memoranda to signing statements, might shape departmental behavior. And to what extent were such actions “unilateral,” anyway, given that both executive-branch agencies and members of Congress had a stake in their issuance, and even in their formulation?

The Dual Executive joins a wave of scholarship exploring these complications, and makes an important contribution by proposing a unifying theory linking the substantive and routine aspects of presidential directives. For Belco and Rottinghaus, these represent contingent, tactical decisions by chief executives who “often have the authority to be independent but do not always act that way,” who “balance the political incentives to act with dispatch and the institutional needs for cooperation” (16, 179). Presidents, in short, are both leaders and clerks – they are both unilateral and ministerial. What are the conditions under which Presidents issue “command” versus “routine” orders? How much does Congress matter, either to empower or to constrain?

The analysis here is largely quantitative, centered on a dataset incorporating EOs and policy proclamations (that is, omitting ceremonial declarations) covering the Gerald Ford through George W. Bush administrations. It may be worth noting that recent Presidents have utilized still other directives, so that some of the contemporary examples the authors use to illuminate unilateral action would not show up in their own data (e.g. Obama's moves on immigration and gun control). Still, the general model has enough utility that future work might extend to these other tools too. The authors find support for several hypotheses, drawn from an impressive swath of American politics research on inter-branch relations.

To wit: presidential choices seem to vary by the stage of the policymaking process, by the President's ideological alignment with lawmakers, by subject matter, and by the salience of the topic on the presidential or legislative agenda. Presidents serve more as administrators, serving Congressional interests, when the two branches have mutual objectives; they are more independent, in turn, when the branches disagree on policy, when Congress is unwilling or unable to act (perhaps because of increasing polarization), or when time is running out for a given administration. The authors also find that topics already on the Congressional agenda are more likely to prompt “command” orders (106). This reflects Alexander Hamilton's astute 1793 observation that “the Executive in the exercise of its constitutional powers, may establish an antecedent state of things which ought to weigh in the legislative decisions.” However, Belco and Rottinghaus suggest that utilizing this “first-mover” advantage is not necessarily a competitive act: it may be proactive without being preemptive, serving as an “assurance to members of Congress of the president’s ability and commitment to execute the policy” (119) or even as an efficient means of providing a focus for collective action. “Not all intervention by the president,” they suggest, “has the nefarious purpose of relegating Congress to a bit player” (120).

Of course, Presidents may have both first- and last-mover advantage, given their ability to use directives to shape the implementation of statute – often in low-profile ways, and when Congress is not in a position to strike back. This can flow from delegated authority and happen well after the fact; the book notes that more than 40 percent of orders cite for their authority laws more than a decade old (88).

The Dual Executive, then, stresses the connections between the executive and legislative branches, thus usefully complicating our notion of “unilateralism” – in this, it pairs nicely both with older work highlighting Presidents’ anticipated reactions to legislative (and judicial) responses, and with newer research measuring those reactions more directly (see, e.g., Fang-Yi Chiou and Lawrence Rothenberg's The Enigma of Presidential Power (2017)). It is more insistent, though, in adding the element of inter-branch teamwork to the equation: “No story about assertive presidential unilateral power can be complete without a passage about congressional assent,” while “Congress can significantly restrict what presidents use to carry their policy into law” (174, 176).

This is true, of course, but hardly seems to be the last word: Congress has been notably lax in protecting its own Constitutional prerogatives in recent years. Given perpetual polarization, that fact is actually in line with Belco and Rottinghaus's predictions. But it may jar their optimism about the state of American institutions.