A year ago, during those foreboding months in which Donald Trump had already been elected but had not yet taken office, I tried to speak to as many moderate Republicans as I could find: “Put your red lines in writing now,” I pleaded with them. “When authoritarian populists take over, they have a way of shifting the goalposts. This will make it easier for you to keep yourself honest.”

In retrospect, I recognize that my appeal was hopelessly naïve—not only because so many moderate Republicans have spectacularly failed the moral tests with which Trump has presented them, but also because so many of the red lines in whose crossing they became complicit would have been difficult to foresee a year ago. Even with the best will, they would hardly have had the imagination to write: “If a member of Trump’s family receives an offer of collusion from the Russian government, and responds, ‘I love it,’ I will acknowledge that he was probably intending to collude with the Russian government.” Or: “If Trump says that there are ‘some very fine people’ at a neo-Nazi rally, I will not pretend that this is a normal thing to do.” Or: “No, I will not continue to support Donald Trump after he endorses a pedophile theocrat for the United States Senate.”

But while many of the violations of basic democratic norms that President Trump and his collaborators have perpetrated over the past twelve months would not have been foreseeable before he took office, most of them had come to seem all-but-inevitable by the time he actually committed them. Trump’s unwillingness to dissociate himself from his most radical supporters was evident throughout the opening months of his presidency. The firing of FBI Director James Comey was preceded by a series of outrageous attacks. Even Trump’s endorsement of Roy Moore in the Alabama special election seemed inevitable by the time he tweeted his support.

These realities make it all the more infuriating that we are now hurtling toward yet another constitutional crisis, and that supposedly moderate Republicans are once again refusing to do anything about it. For the better part of a month, Fox News and other conservative media outlets have been smearing Special Counsel Robert Mueller, all but calling him an enemy of the American people. Over the past week, a series of senior Republicans have joined in the chorus of delegitimation, with a host of voices—from Mike Conaway, who leads the investigation of Trump’s campaign on the House Intelligence Committee, to John Cornyn, who heads the Senate equivalent—insinuating that it is time to wrap up the special counsel’s investigation.

We are, in other words, once again reaching the point when something that had seemed outlandish a few short months ago is starting to feel virtually inescapable. Now that the outriders have done their work, there is every chance that Trump will fire Mueller within the next month. And even if the president was telling the truth when he denied any intention of doing so a few days ago, he could well cite Mueller’s invented infractions as an excuse for pardoning his closest associates or defying judicial orders.

It is anybody’s guess who will win the next round in the death match between the president and the American republic.

Like more than a hundred thousand other Americans, I recently took a pledge to take to the streets the moment Mueller is fired (if he is). Perhaps our protests will make a difference. Perhaps they will even manage to shame those supposedly moderate Republicans who have, again and again, proven to be astoundingly unwilling to live up to their professed principles. For now, the other branches of government still retain the power to check the president: Congress could, for example, revive the independent counsel statute, allowing Mueller to be reinstated without fear of further interference from the executive. This would go a long way toward containing the damage Trump is trying to wreak.

Miracles do happen, and Christmas is around the corner. As that touchingly patriotic animated movie An American Tail would have it, one should “never say never.” And yet, I fear that there is a simple reason for skepticism about whether Congress will defend the rule of law: over the past year, Republicans had a comparatively easy way to police this particular red line without overtly opposing Trump. “Obviously,” they could have said, “the president would never do anything as crazy as this; but if he did fire Robert Mueller, I would have to support congressional action to reinstate him.” Indeed, following that rationale, they could easily have signed onto bipartisan legislation that would have stopped Trump from being able to fire Mueller in a fit of rage in the first place.

Instead, virtually all of them refused to comment; the few who did actively conspired in undermining Mueller. (When former attorney general Eric Holder claimed to speak “on behalf of the vast majority of the American people,” when he said that “any attempt to remove Bob Mueller will not be tolerated,” for example, Senator Cornyn replied, simply, “You don’t.”) Why, then, should we expect congressional Republicans to take the far more difficult step of overtly opposing the president after he has attempted to put an end to the Russia investigation?

As the bitter year of 2017 draws to a close, and the decisive year of 2018 begins to dawn, the fact that we are spending yet another holiday season with a strong sense of foreboding suggests an important lesson for the defenders of liberal democracy. Over the past months, we have become experts at making noise when red lines are crossed. After the first travel ban, we rushed to airports around the country. After Charlottesville, we held huge rallies to protest hate. Should Mueller be fired, we will once again take to the streets, feeling the comforting rush of being surrounded by thousands of likeminded people.

All that is good. But the truth of the matter is that it still allows Trump and his accomplices to set the agenda: they act, we react. While we spend our time bemoaning one red line that has just been violated, the White House can prepare its assault on the next.

That is why our resolution for 2018 should be to defend our institutions in a more proactive manner. When Trump and his supporters start to signal what outrage they might commit next, we need to immediately bring maximum pressure to bear on the most persuadable members of the president’s coalition. Doing so will be difficult and exhausting for the resistance. But a great prize beckons: If we manage to defend the basic rules and norms of the American republic over the next twelve months, and Democrats win back control of the House or the Senate (or both) in the midterm elections, the hour of greatest danger will have passed. And if, in 2020, we manage to rid ourselves of the most unsuitable president in this country’s history, the even more cumbersome work of rebuilding the rules and norms that have underwritten the American republic for the past two hundred and fifty years can finally begin.