Three distinguished scholars of the presidency—John A. Dearborn, Desmond S. King and Stephen Skowronek—published an intriguing essay at The New York Times this morning about taming presidential power. Their case is that constitutional combat between Congress and the President favors executive power. Instead, they write, Congress should “assert its capacity to engage the president and the executive branch in ways that foster cooperation in issues of governance.”

The authors note that Congressional attempts to play hardball on the separation of powers have tended to trigger backlashes: Presidents have responded by asserting executive power, and their control over the executive branch, more stridently, and the courts have tended to back them up.

This argument is compelling. Nonetheless, I have some reservations. First, it is true that presidents have resisted attempts to curb their power, but it is also true that Congress, often acting on partisan rather than institutional motives, has too readily backed down. Second, courts have tended to back presidential power, but that is less a case for acceding to executive authority than it is one against running to the courts for protection against the neighborhood bully.

Congress’ spending power alone—which Federalist 58 calls “the most complete and effectual weapon with which any constitution can arm the immediate representatives of the people, for obtaining a redress of every grievance, and for carrying into effect every just and salutary measure”—makes legislators a match for the presidency. But legislators must be willing to use it, including punitively. The problem is that Congress is generally more interested in opening that spigot than in closing it off. The power of the purse is no different from any other power: Congress has to be willing to use it. That should entail some attention to creative solutions to a legislature’s endemic collective-action problem, especially when it is not motivated to act.

Dearborn, King and Skowronek argue that “the resurgence of constitutional formalism” in defense of the separation of powers has actually undermined legislative authority. Lurking beneath that point is another, one more difficult to answer: At what point does constitutional conservatism become constitutional nostalgia? In other words, it may be true both that engagement between branches of government violates the ideal form of separation of powers and that such is where we are. Those of us pressing for formalism may simply be mourning what is already lost. That implies a transition from separation of powers to something closer to a parliamentary regime that is divided not between branches of government but rather between those in power and those in opposition.

Nostalgia is seductive, especially for those inclined to look to custom for guidance. For those of us who are vulnerable to that temptation, Dearborn, King and Skowronek provide a useful corrective. Their argument that engagement is likelier than conflict to tame executive power deserves a reckoning. On the other hand, if we are going to concede such a fundamental change in the nature of the regime, we should do so self-consciously and with an awareness of the risks. Those risks include acceding to the idea that presidents occupy the driver’s seat in American politics and that Congress, riding shotgun, merely provides navigational tips, and applies an occasional emergency brake, along the way.