The American Constitution is a fossil record. Beneath the rocky soil one finds layer upon layer of strange deposits, atavistic survivors of bygone eras, such as the Electoral College. One of the most curious specimens preserved in the sediment is the United States Senate.

Why does it continue to exist? With the ratification of the 17th amendment, the Senate's raison d'être was eliminated. Bicameralism has always called for a body of common representatives elected by the people and a revising upper chamber of appointed grandees. The former, as constitutional theorists have long argued, are prone to enthusiasms that must be checked by the wisdom and prudence of the latter, even — indeed, especially — when doing so might prove unpopular. Having two distinct bodies that are both said to directly represent the will of the same electorate is on its face nonsensical. (This is the argument often made against reforms that would turn the British House of Lords into a purely elected body.) The few powers the Senate continues to enjoy might easily be given to the House — or dispensed with altogether. Indeed, the most important of these, the ability to confirm judicial and other presidential appointments, is becoming purely ceremonial.

This is not to suggest that we no longer have a de facto upper chamber. The real Senate of the United States meets not in the north wing of the Capitol but just across First Street. I mean, of course, the Supreme Court.

Why is this not explicitly acknowledged, I wonder? Are the nine not appointed rather than elected? And do they not legislate, at times clarifying, at other points frustrating the will of the two lower chambers? When we read about the outcome of a case before the court we are told how the justices "voted." This should put paid to everything our middle school civics teachers tell us about the separation of powers and the disinterestedness of the judicial process. A perfect illustration of this is NFIB v. Sebelius in 2012, when, after some horse trading between Chief Justice Roberts and his liberal colleagues, the Supreme Court essentially revised the Affordable Care Act. This is exactly what upper bodies are supposed to do in bicameral legislatures.

There is nothing especially strange about this. The rise of the senatorial high court was a simple matter of competing pressures, of finding a new outlet for constitutional energies when older channels were suddenly closed.

This is why I find it difficult to make sense of conservative complaints about "legislating from the bench," which under President Trump are increasingly becoming the province of liberals and progressives as well. It is also why I find it so easy to understand the arguments being revived by the latter in favor of so-called "court packing," a scheme to increase the number of seats on the court in order to counteract what they imagine will be an imminent conservative super-majority.

Remaking the composition of the upper chamber has been a ubiquitous threat in Anglophone constitutional disputes. It was nearly carried out in 1832 by King William IV, who needed Whig peers in the Tory-dominated House of Lords in order to ensure the passage of the Great Reform Bill. It has reared its head in Britain again very recently with the rise of life peerages and the expulsion of all but a small token representation of hereditary peers. In this country the size of the de facto upper chamber has been altered many times, including by President Lincoln, who appointed a Unionist 10th justice at the height of the Civil War. After the war the number of justices dropped to seven and would have returned to the original number of six if it had not been for the Judiciary Act of 1869. Franklin D. Roosevelt famously tried to expand it to as many as 15 in 1937.

When the idea is revived in earnest, I expect it to involve the creation of a vast number "term" justices, who will serve for four or six years, and the phasing out of lifetime appointments. This will make members of the court the explicit creatures of the party in control of the White House.

Such a scheme would certainly be in keeping with other constitutional trends. Like those of the House and the nominal Senate, the prerogatives of our quasi-judicial upper chamber are fast disappearing. The legacy of the court's quasi-legislative rulings on the most central questions of our age obscures our ability to see a new pattern emerging, one that involves a broad deference to the executive branch — especially toward decisions made by the various administrative bodies whose authority flows directly from the presidency.

Making predictions is often a mug's game. I would not presume to suggest that I know exactly what American government will look like in 20 or 30 years. But the movement of our politics, not simply during the last 20 or so years but for the entire history of the American republic, has been a march in the direction of executive power.

This should not be surprising. It is scarcely ever remembered that for many of the men of 1776 the great enemy was not King George III but rather the British Parliament, which had wrongfully presumed to govern the colonies in his stead. What their revolution sought to undo was the Hanoverian settlement of 1688-9, not the principle of monarchy itself. It is debatable whether they accomplished this immediately. That their ambition will be sooner or later fulfilled, however, seems to me beyond argument.

What is even clearer to me is that this is more or less what the American people want. Everyone has his token arguments against the power of the executive when the faction he opposes holds court in the ovular throne room at 1600 Pennsylvania Avenue; no sooner has their preferred candidate received the purple, however, than they perform the mental jujitsu necessary to justify executive omnipotence. Sometimes the argument is merely that Congress is recalcitrant or otherwise negligent in performing its ordinary duties, such as the passage of budget resolutions; occasionally it is that we have reached some kind of crisis that cannot be resolved through ordinary democratic means. This is all nonsense. When Barack Obama remakes our immigration system, including the de facto definition of citizenship, with the stroke of a pen or when Donald Trump appropriates unobligated funding from the Department of Defense, they are doing what they were elected to do.

No one in particular is to blame for this. The divisions in American society are well-nigh unbridgeable. We do not disagree about the kind of prudential questions the democratic process is supposed to adjudicate — indeed, there is widespread agreement such matters as whether we should invest in new infrastructure, whether generational debt servitude is a good idea, whether we ought to have a less financialized economy with higher median wages, and whether the provision of health care should continue to be an unstructured and unaffordable mess. Not so when it comes to loftier questions about what constitutes human life, say, or the definition of marriage and the nature of family life.

Everyone wants his own Caesar. This may be a failure of our collective imagination. It may be a necessary centralizing response to the complexities of modern life. It may be a belated post-Enlightenment concession to the wisdom of the Middle Ages. It might simply be the true inheritance of our Founding Fathers. It is difficult to say. But it is also undeniable and, very likely, inexorable.

Sooner or later every institution, even one as seemingly omnipotent as the Supreme Court, will bow before the Resolute desk.