When I teach comparative politics courses, I often ask students to compare the relative benefits and drawbacks of America’s presidential system with the U.K.’s parliamentary model.

In response, whether due to familiarity or genuine admiration, most students end up mounting a defense of the U.S. model based on the separation of powers. It often makes me feel like the related idea of “checks and balances” is one of the few civics concepts that is still successfully taught to high school students in this country. And indeed, the argument the students tend to make is not all without merit, as there is something unambiguously noble about creating a system designed to resist the tyrannical impulses of human beings.

It is also increasingly a lie.

Neither the hallowed phrase “separation of powers” itself nor “checks and balances” appears in the text of the U.S. Constitution. Nor does the word “oversight.” Nor does the word “coequal.” The Constitution is a document that barely defines the scope of the judicial branch at all and so deficiently defines the powers of Congress, the presidency, the states and the federal government that we have spent the better part of two and a half centuries fighting about it.

The separation of powers is so inadequately outlined that James Madison devoted Federalist No. 47 to critiques that the U.S. Constitution insufficiently divided power between the different branches of government. “The accumulation of all powers, legislative, executive, and judiciary, in the same hands, whether of one, a few, or many, and whether hereditary, selfappointed, or elective, may justly be pronounced the very definition of tyranny,” he wrote, somewhat defensively.

But he also noted that these powers cannot be entirely separated. He wrote in Federalist No. 48 that the separation of powers as envisioned by the Constitution “does not require that the legislative, executive, and judiciary departments should be wholly unconnected with each other.” In other words, the separation of powers by its very nature involves, for instance, granting some powers to Congress over the executive branch and vice versa. Or as legal scholar Nat Stern argued in a 2016 law review article, the “maintenance of separation of powers and the checks and balances that accompany it is not a self-executing scheme.” It requires constant interplay between the branches, with the Supreme Court acting as the ultimate arbiter of power’s boundaries.

Never has that been more obvious than today. The failure of the separation of powers scheme can take three forms. One is a branch claiming for itself powers that are clearly granted exclusively to another, as with President Trump taking money that Congress authorized for one purpose and using it for something else entirely. Another mode of failure is for one or both branches to simply fail to use their authority to check the others when called for, like when Congress failed to challenge President Roosevelt’s executive order interning Japanese-Americans during WWII. Finally, an obvious instance of one branch overstepping its authority can be validated by the courts rather than blocked, as when the Supreme Court absurdly voted to uphold the internment in Korematsu v. United States.

Due to a combination of Republican scheming, Constitutional hardball and hyper-partisanship, we are actually experiencing all three of these failures simultaneously. On the one hand, a sharply divided country characterized by hyper-partisanship means that Congress is incapable of exercising its most important powers over the president. Unless one party captures 67 seats in the Senate while improbably losing the presidency, the president cannot be impeached, and without similar margins in the House, vetoes will almost never be overridden. In and of itself, this is an invitation for the president to exercise what Madison called “overruling influence” over the other branches. Who or what will stop him?

It is the judiciary that is supposed to rein in attempts by both Congress and the president to overstep the boundaries of their respective authority. And it is here where we have arrived at the most dangerous features of Trumpism and the long-term efforts of the Republican party to politicize the courts to their advantage.

The president has frequently attacked the legitimacy of the federal judiciary when it issues decisions he doesn’t like. When a district court judge named Haywood Gilliam, Jr. blocked the president’s attempt to use national emergency powers to reallocate money for the border wall, the president called him “another activist Obama appointed judge.”

More dangerously, Vice President Pence recently unveiled plans to ask the Supreme Court to strip district and appellate courts – many of which still have a majority of justices appointed by Democratic presidents despite the GOP’s furious efforts to fill vacancies as quickly as possible –of their ability to issue nationwide injunctions. The president and his allies want to prevent all but the Supreme Court itself, which only hears a tiny fraction of all cases appealed to it, from interfering with the administration’s dubious and rampant exercise of executive authority.

Of course, that court’s majority was obtained by denying a Democratic president the right to fill a vacancy, a profound violation of the judiciary’s role in American democracy, since faith in the courts depends on the public’s estimation that they are staffed fairly. And Trump’s loading of the lower courts with baby-faced, Federalist Society ideologues was itself made possible by Mitch McConnell’s decision to halt nearly all of Barack Obama’s nominations in 2015 and 2016.

So what we are seeing looks less and less like the separation of powers as envisioned by the architects of the Constitution, and more like a creeping Guardian Councilization of America.

The Guardian Council is an unelected body of 12 Iranian jurists who can veto any legislation passed by the elected parliament. The Guardian Council also vets presidential and parliamentary candidates before they can stand for office. It is therefore the case both that Iran frequently holds spirited and contested elections and also that the country is deeply authoritarian. What looks like a kind of separation-of-powers arrangement is subverted in practice because real decision-making authority rests with the Guardian Council and ultimately with the country’s Supreme Leader. The logic of authority is circular.

We think that this cannot happen here only because the idea that the Constitution created an easy system of checks and balances is so deeply ingrained. Many of the Constitution’s checks, though, are customary and depend on legal interpretations – like oversight powers – and could be set aside by courts friendly to the president, who would then effectively be beyond any kind of democratic accountability save for the next election. A high court which owes its ill-gotten majority to that same president, takes away the power of lower courts to halt unconstitutional laws, and then issues decision after decision that makes it difficult if not impossible for the opposition to actually win elections would soon function as a kind of American Guardian Council, with the executive branch as the de facto Supreme Leader.

Most political scientists will tell you that a vast and problematic expansion of executive power significantly predates the Trump era. But the president’s aggressive maneuvers threaten not just to somewhat weaken Congress in relation to the executive branch but rather to call into question the basic viability of the Constitution’s division of powers. That is why the Supreme Court’s decisions in the matters regarding President Trump’s arrogation of authority to himself and his administration are so important. The future of much more than my lesson plans depends on it.