Each week, In Theory takes on a big idea in the news and explores it from a range of perspectives. This week we’re talking about executive power. Need a primer? Catch up here.

Adrian Vermeule is the John H. Watson professor of law at Harvard Law School. His next book on executive power, “Law’s Abnegation: From Law’s Empire to the Administrative State,” will be published in September.

In the spirit of John Lennon, let’s imagine, all starry-eyed, that there’s no U.S. Congress. In this thought experiment, the presidency and the Supreme Court would be the only federal institutions, along with whatever subordinate agencies the president chose to create. The court would hold judicial power, while the president would make and execute laws. The president would be bound by elections and individual constitutional rights, but there would be no separation of legislative from executive power.

Would such a system be better or worse than our current system? How different would it be, anyway?

The long-run drift of institutions and events is clearly toward, rather than away from, de facto presidential lawmaking. Recent years have seen many examples of aggressive executive action by President Obama: on health-care regulation, carbon emissions, immigration, diplomacy and war. (The president’s recent actions on gun control aren’t actually very aggressive.) The legal justifications vary. Sometimes these are agency regulations justified by reference to a delegation of authority from Congress, under laws that are broad or vague. Sometimes a policy statement announces an exercise of “prosecutorial discretion” that is cast in general terms. Sometimes the president relies explicitly on constitutional powers, even in the teeth of contrary congressional statutes. Whatever the justification, presidential initiative tends to prevail unless other institutions rouse themselves to take action.

Of course, we have not arrived at a constitutional system that lacks a Congress — not yet. Congress still clings to the power of the purse, although Obama has interpreted appropriations creatively, to say the least, in the health-care setting. Presidents still do not formally enact “laws” in the sense of statutes, but they can promulgate executive orders that bind federal agencies and executive branch officials within the scope of the president’s legal authority. Mostly thanks to laws passed by Congress over the past two centuries, many of which are broad or vague, these executive powers are vast. Many critics fear a slippery slope in which the president becomes the operational lawmaker in chief.

But the real question is whether a system without Congress would be worse than what we have now. A single official holding both the powers of lawmaking and law execution would have both virtues and vices. The blurring of accountability that the current system enables, especially in periods of divided government, would be diminished, as a single, nationally elected official would be responsible in principle for lawmaking. Policy might switch back and forth more quickly with the vagaries of partisan control — although the president’s delegated authority is sufficiently capacious today that such switches occur anyway, with every partisan change of administration.

Such a system would resemble the classical Westminster-style parliamentary systems that fuse legislative and executive powers, in which the incumbent party can make rules more or less at will, subject only to the shadow of elections. Ironically, the abolition of Congress, by streamlining the process of lawmaking, could produce a jury-rigged, second-best version of parliamentary government in the United States.

It might even improve upon our current regime, which combines a Congress that pretty much everyone detests with a presidency despised and distrusted by about half of the people, half of the time. Subtracting the most detested branch might make everyone better off, even those who happen to find themselves in opposition to an incumbent president for the time being. After all, that president, of either party, will have no other institution to blame for bad laws made or good laws not made.

The commonplace objection to a United States without a Congress is not that it would be a bad United States, but that it would not be the one our Founders created. There is an obvious sense in which that is true, but there is also a somewhat less obvious sense in which it is false. The Constitution created a set of institutions exercising separated powers, but those institutions themselves created the modern powerful presidency and bureaucracy, in part because the institutions were too limited and wisely recognized their limitations. Critics who would restore the original Constitution should consider the possibility that if the presidentialist state did not exist, Congress would just create it anew, in an eternal recurrence of legislative abnegation.

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