Almost exactly forty years ago, a nuclear reactor near Harrisburg, Pa., almost had a meltdown. Three Mile Island then became the poster child for the anti-nuclear movement. 

Nuclear reactors are dangerous. They are therefore designed with multiple and redundant systems to avoid catastrophe. It was the failure of a backup system at Three Mile Island that was ultimately deemed a “key failure,” that then triggered a further set of failures leading ultimately to a partial core disintegration.

{mosads}Governments too are dangerous. Constitutions are crafted to check that danger, by building into the system multiple checks and backups. If one part goes bad, they are designed to give others the opportunity to fix it. And as with Three Mile Island, after a near-catastrophe, the question is always not just what the trigger was, but also why the backups failed so spectacularly. 

This is the perspective we need to bring to the Trump shutdown. For more than two years, the media has been focused on the catastrophe that is this president: His failure of integrity; his failure to grasp the simplest points of policy; his utter refusal to work, to learn or to listen; his basic, in a word, instability. 

But the framers of our Constitution did not leave us vulnerable to a failed president. Instead, they crafted that document to give other branches and institutions adequate opportunity to check any failure, and more importantly, a moral responsibility to step-up if needed. 

That primary check is Congress. And the failure that this shut down represents is not just, or even especially, the failure of Trump. It is also the failure of Congress. Specifically, it is the failure of the Senate. Or more precisely, Republicans in the Senate. Or more precisely still, Kentucky Sen. Mitch McConnell. 

There is no way that McConnell believes that the Trump Shutdown is justified — either politically or morally. There is no way he believes that any “crisis” on the border will be addressed by a wall that Mexico will not pay for, and that the American people have overwhelmingly rejected. McConnell understands the nature of American constitutional government. It is McConnell’s failure alone that allows this crisis to continue. He alone could exercise the moral courage to tell this president that America is going to move on. McConnell is the relief valve that would not turn on. 

Unlike with nuclear power, we will not have the chance after this crisis to turn away from the idea of government. What the Republicans need to ask now is whether America will turn away from them. America already holds the president responsible for the shutdown. But the embarrassment of the last two years — itself now overwhelmingly rejected by voters—is the failure of moral courage by Republicans. The Trump shutdown will not just be the poster child for Trump’s presidency. It will be the defining measure of the capacity of his party to govern. It has been obvious to many Republicans for many years that tying the party to this president was a mistake. Even without a meltdown—like a TSA-related disaster or a food-safety related outbreak—the party should recognize it will pay dearly for this mistake. 

Lawrence Lessig is Roy L. Furman Professor of Law and Leadership at Harvard Law School, and founder of EqualCitizens.US. His latest book is “America Compromised.”