This post is part of Polyarchy , an independent blog produced by the political reform program at New America , a Washington think tank devoted to developing new ideas and new voices.

A year ago, as we approached the opening days of the Trump administration, it was still possible to make a hopeful, albeit long-shot, argument that 2017 could be the year Congress finally started to reassert itself as an institution. And that the cumbersome checks-and-balances system the framers set up would finally pay off and prove its worth as a tool to limit the power of a would-be demagogue.

The rationale went something like this: Congressional leaders of both parties understood the unique dangers that a President Trump posed to the country and the world. Therefore, they would finally invest in resources and capacity to assert the authority of the first branch of government, most visibly through vigorous oversight. Party be damned — the fate of the nation was more important, and it was time for Congress to stand up as an institution!

After all, “separation of powers” was our civic religion, right? In James Madison’s famous phrase from Federalist 51, on checks and balances: “Ambition must be made to counteract ambition. The interest of the man must be connected with the constitutional rights of the place.”

Obviously, this has not happened. Yes, here and there, congressional Republicans have made a few modest attempts to challenge the president. But mostly they’ve been willing bystanders or sycophantic cheerleaders. Yes, Congress imposed sanctions on Russia for election interference. But the Trump administration has so far delayed implementing them, and there’s been no visible pushback.

And those few Republicans who have spoken out against Trump, like Sens. Jeff Flake, Bob Corker, and John McCain, are on their way out, either voluntarily or involuntarily. Whatever power they have, they’ve not used it visibly to do more than give some speeches. Consider Corker’s meek response to the administration’s delay in implementing the Russia sanctions: “I'm going to get on the phone with someone.” (Way to use your power, Senator. You get on that phone! To someone. Anyone.)

With few exceptions, Republicans in Congress have made a simple political calculus. Their electoral future is tied to Trump’s success. Trump is now the face of the Republican Party. And among Republicans, he remains pretty popular. If congressional Republicans forcefully challenged Trump, they’d bring on a primary challenger, destroy the Republican brand, or both. Even if most preferred to see Mike Pence in charge, the costs of getting there are too high.

The founders’ mistake

In writing the Constitution of the United States, the framers were attempting to balance competing views. Some, most notably Alexander Hamilton, wanted a strong and energetic executive. Others, most notably Madison, wanted the legislature to be preeminent.

While the framers may have disagreed on the balance of legislative versus executive power, there was one topic they did agree on: political parties. Political parties, they all thought, were terrible, awful, divisive forces, to be avoided at all costs. If allowed to form, political parties would tear the young nation apart.

And the best way to prevent partisan majorities from forming was to divide up power across so many competing institutions that it would be impossible for partisan majorities to form. Political scientist E.E. Schattschneider puts it this way, in his classic Party Government:

The authors of the Constitution set up an elaborate division and balance of powers within an intricate governmental structure designed to make parties ineffective. It was hoped that the parties would lose and exhaust themselves in futile attempts to fight their way through the labyrinthine framework of the government.

The president and the legislature would be separate branches. An “electoral college” would nominate multiple candidates for the presidency, and then Congress would select among those candidates. There would also be a court system, a third branch, to provide additional checks.

With the exception of the election of 1824, however, the Electoral College never worked as planned. Instead, presidential elections evolved into a single winner-take-all national plebiscite election, with two major parties competing for what was frequently a very narrow majority.

Because the president is the only actor in the system who runs for office nationally, he has historically defined the party brand. And because the electoral fate of congressional partisans is linked to the brand of the party, they have a strong interest in going easy on fellow partisan presidents, while being tough on opposing partisan presidents. As a result, separation of powers has long been a dead letter without divided government.

There is no separation of powers without divided government

Think of all the important moments when Congress has meaningfully checked abuses by the executive branch: Watergate, the 1975 Church Committee on wide-ranging domestic spying abuses by the CIA and the FBI, the Iran-Contra hearings. These were all moments of divided government, with Democrats in Congress and Republicans in the White House. Also note: The only two impeachment votes taken in Congress (Andrew Johnson in 1868, Bill Clinton in 1998-’99) came when Republicans controlled Congress and Democrats controlled the White House. None of these notable separation of powers moments would have taken place under unified government.

One might partially object to the above statement, and note that the courts, the third branch, have checked some of the Trump administration’s plans, notably the travel ban. But primarily, it has been liberal justices challenging the Trump administration. The conservative Supreme Court gave the administration the thumbs-up on the ban. And if the Trump administration succeeds in its efforts to remake the courts by appointing conservative justices, does anybody expect them to challenge the administration? The courts are more polarized than ever too.

Of course, the framers never anticipated this problem. Again, they thought American government would work without parties. And yet: It took a single Congress and Madison’s Republican Party was doing battle with Hamilton’s Federalist Party, voting in predictable patterns, calling each other nasty names (like “monocrat” and “Jacobin”), and fighting over the provision of presidential furniture. Whatever barriers Madison the framer enacted to make it hard for parties to form, Madison the partisan Congress member quickly found a way around them.

Perhaps the framers should have anticipated this. But they were humans, like everyone else. They couldn’t anticipate everything. And they were optimistic that they had designed a system of government that would frustrate partisan majorities from forming, solving the complex problem of divisive factions in a new and original way.

What if the separation of powers system really is a myth?

Perhaps at some point, we’ll return to an era of overlapping parties and weak partisanship (like we had in the 1950s), in which it was at least conceivable that institutional loyalty would be more important than partisan branding. But in this current moment of hyperpartisanship, that seems highly unlikely. Parties have never been more divided. Looking back on 2017, one wonders: At this point, what could possibly unite congressional Democrats and congressional Republicans against a president of one of the two major parties?

Where does that leave us? For the immediate moment, anyone who believes in the importance of separation of powers should support Democrats taking back the House and the Senate in 2018.

But this is a limited answer. And perhaps conservatives might say: This is too high a price to pay for a balance of powers government, just as liberals would say the same thing if the roles were reversed. After all, divided government under high partisan polarization is really just gridlocked government, and whatever oversight comes out of it might wind up as an endless fishing expedition to find something, anything, that can bring down the opposing party’s president. But that is the system we have.

And yet … what if the framers had admitted that parties were indeed inevitable, and would stretch across the branches of government? Would they have come up with a different design to balance powers, and to avoid the great danger of majority tyranny they were so worried about?

More recent democratic constitution writers have dealt with this problem through various means. They’ve turned to proportional voting, which creates multi-party systems that require broader coalition building and balanced cabinets. Some countries have even mandated cabinets that are always balanced between competing parties and competing factions or regions. Most democracies also make it easier for the legislature to replace an incompetent executive through votes of no confidence and/or by calling new elections. Impeachment is a clumsy and difficult mechanism.

Certainly, we Americans tend to take great pride in our democratic institutions, and find it inconceivable that our Constitution is not perfect. But while the framers were wise and thoughtful men, they did make some mistakes. They did not anticipate political parties. They thought ambitions and loyalties would be to institutions, not to parties. But as the events of 2017 have made clear, once again, partisanship is more powerful than institutional loyalty. There is no separation of powers without divided government. It’s time to face up to this reality.