The media is calling Thursday Donald Trump’s “day of chaos.” And there’s truth to that. From Defense Secretary Jim Mattis’s shocking resignation letter to Trump’s decision to shut down part of the government over funding for his border wall, Thursday was, well, a day. But in centering the narrative on Trump, we obscure a more consequential truth: The ongoing disaster roiling American governance is the Republican Congress’s fault, and they need to be held accountable for it.

Our system of government was built by men who predicted and feared an out-of-control president. So they built another, more powerful branch of government able and expected to check a raging executive. Congress, not the president, comes first in the Constitution. In focusing so much on Trump, we focus too little on Congress’s Republican leadership, and the job they are failing to do.

On Thursday, Mattis, the member of the Trump administration congressional Republicans most admire, resigned, saying he could no longer serve a president who believes in wrecking our alliances and allying with authoritarians. It’s believed Mattis is only staying until February so he can run the NATO summit, as he doesn’t trust the president to do it himself.

There are legitimate debates to be had over Trump’s foreign policy, but the view of the GOP leadership has long been clear: Mattis’s views on foreign policy should be heeded. It was, in fact, his presence in the Trump administration that calmed many Republicans about Trump in the first place.

But now, after serving in Trump’s Cabinet since the dawn of the administration, Mattis has issued a damning indictment of the president, saying he can no longer ignore how fundamentally Trump’s views differ from his own, and from the consensus that has defined post-World War II American foreign policy. For congressional Republicans, the call isn’t just coming from inside the house. It’s coming from inside the house — and it’s Dad.

So what will Senate Republicans do now? Are they going to ask Mattis to testify on how Trump really runs his foreign policy? Are they going to refuse to confirm anyone they think is less independent than Mattis to replace him? Or are they just going to send some distressed tweets and move on? The answer, I fear, is obvious.

Let me ask one other question: What would Senate Republicans do if they held the majority and this chaos was engulfing a Democratic White House?

But it wasn’t just Mattis. On the same day, House Republicans decided to do nothing on another front. In fact, they did worse than that. They enabled Trump’s impulsive decision to send the country barreling toward a government shutdown.

Trump blew up a deal that Republicans in Congress had made — and that he had accepted — to fund the government. He did so recklessly, with no planning for the aftermath, with no theory of how to negotiate out what he wants. He did so because he didn’t get money for his wall, and he didn’t get that money because he didn’t have the votes or the public support. But House Republicans, rather than sticking to their initial plan of governing the country responsibly, meekly indulged his tantrum.

Now Trump intends, under the rubric of enhancing American security, to force “a shutdown that will last for a very long time” of, among other agencies, the Department of Homeland Security and the Department of Justice.

Congressional Republicans know this is lunacy. They don’t have the votes for what Trump wants, Trump isn’t offering Democrats anything to get more votes, and America’s security isn’t served by paralyzing the agencies responsible for it. That’s why Republicans didn’t do this in the first place.

Trump, however, had no power to force this shutdown on his own. Congressional Republicans and Democrats had come to an agreement. If Trump vetoed, they could have overturned the veto. The Constitution gives Congress vastly more power than the president — the president can’t even force a vote on legislation, while Congress can pass a bill even over the president’s objections. But congressional Republicans are choosing, once again, to indulge Trump rather than serve the country.

The real story of this era is not Trump’s behavior. We can’t fault Trump for being Trump. As the lesson of his favorite parable goes, we knew damn well he was a snake when we took him in. But we can fault Republicans in Congress who are failing to do their jobs, and making a mockery of the constitutional system they claim to revere in the process.