What does decline sound like? I imagine equal parts self-pity and self-flagellation, moral outrage and exhaustion. Once we could have heard it from the original Capitol Hill, the seat of the failing Roman Republic. As Caesar told Rome’s Senate, “Certainly there was greater merit and wisdom in those who raised so mighty an empire from humble means, than in us, who can scarcely preserve what they so honorably acquired.” His enemy Cato responded, “There were other things that made them great, which we lack: industriousness at home; fair government abroad; minds impartial in council.” They lived in an era of decline, and they both knew it.

Do we? That exchange resonates as we look again over last year’s bruising budget battles—which, thankfully, appear to have reached their wearying apotheosis. In unsteady times, we’re compelled to look back: Tea Partiers imagine themselves as revolutionary Americans; revolutionary Americans (churning out pamphlets under names like “Publius,” “Brutus,” and “Cato”) imagined themselves as republican Romans; and those Romans measured themselves against the generations that bequeathed them an empire. We live in a nation modeled on Rome, founded by men who modeled themselves on Romans—and having traced Rome’s history in outline, from backwater republic to imperial power, it’s natural to wonder if the next step is ours as well.

It’s a fair worry. Across time and place, the breakdowns of republican governments share eerie similarities, as political conflicts spill beyond the bounds of the norms designed to hold them in check. Rome’s example warns us that a cycle of crisis politics, once entered into, grows increasingly difficult to escape. There is reason to believe that we’ve entered into just such a cycle. But there is also reason to hope that we can respond with a rededication to political norms—not with the panicked cries of tyranny and self-fulfilling predictions of collapse that doomed Rome.

Brinksmanship, “nuclear options” and shutdowns are not unique to American politics. The Roman Republic’s final years were increasingly prone to political conflicts so intractable that they left the government paralyzed. In 60 bce, Cato, the leader of Rome’s traditionalist optimas faction, ground the Senate to a halt for months through unprecedented use of the filibuster. His prime target was a program of land reform that would distribute public farms to Rome’s veterans, a measure that the optimates feared would create the constituency for a military tyrant.

For the following year, Rome elected a government headed by Caesar, who promised to carry out the land reform, and Cato’s son-in-law Bibulus, who pledged to stop it (proving that we aren’t the first to struggle with divided government). Cato, a man of great personal courage but the politics of a brick wall, again blocked a Senate vote on the land bill. Bibulus attempted to halt public business by declaring every remaining day on the legislative calendar a religious holiday; as he announced to the public, “You shall not have this law this year, not even if you all want it!” Caesar answered with a constitutionally questionable step of his own, bypassing the Senate and pushing land reform directly through the Roman people’s assembly. Bibulus retaliated by barricading himself in his home, boycotting the government and postponing the next election for three months.

Though the victory was Caesar’s, the episode left a deep legacy of bitterness. Three years later, the optimates went on legislative strike again, in renewed protest against Caesar’s political faction. Rome’s hardline senators shut down the chamber, dressed in black mourning clothes, and, in the words of the ancient historian Cassius Dio, “spent the rest of the year as if they were in bondage and possessed no authority to choose officials or carry on any other public business.” Most significantly, they refused to schedule elections. The Republic faced the prospect of a new year with no elected government at all, until the senators backed down and allowed a vote on the calendar’s final day. By this point, stalemated government and manipulation of elections had become routine: Over the Republic’s last decade, elections were postponed in five consecutive years. And in the midst of the squabbling, the Forum heard louder and louder cries for a strongman to save Rome from the muck of self-government.

History has been called “a distant mirror” for good reason. We can see our own features reflected in the past, but only vaguely. A distance of 2,000 years means that there are no easy reflections between this shutdown story and ours. But at the same time, history would be worthless to us if we didn’t try to translate truths from one age to another. And one truth that does seem to translate is this: In republican government, norms matter profoundly.

Political elites aren’t simply bound by written rules; they’re bound as well by unwritten rules that are developed and refined in practice. We wouldn’t want to write the entire code of political behavior into law. Instead, we prize freedom of action and flexibility; we understand that a code of written rules that tried to anticipate every situation would be an oppressive failure. Perhaps, as a political community, we also value systems that depend on a degree of mutual trust in order to function. And yet our reliance on unwritten rules leaves us vulnerable. Built over generations of conflict, compromise and accommodation, norms can be discarded in an instant. They are far easier to break than to build—and breaking them only takes the defection of one side.

The Roman Republic was nearly five centuries old when it collapsed. In that time, it had developed norms against permanent filibuster campaigns, boycotts of government, bypassing the Senate to enact policy and postponement of elections. All of the steps I’ve described were legal. They were also disastrous. Collectively, layered one on the other, they normalized a state of crisis politics.

But given how far we’re already traveled down the road of norm failure, there is also some reason to fear that these developments are too little and too late. When norms collapse, they often fall in unpredictable cycles of resentment and recrimination. As two sides engage in tit-for-tat behavior, or as one side discovers that unwritten rules are hollow, republics can suffer cascades of norm-breaking. The last years of the Roman Republic saw unwritten rules called into question across nearly every dimension of its political life. Taboos against multiple terms in the highest office, and on “extraordinary,” multi-year military commands—both conceived as checks on elite ambition—were discarded. The Senate broke precedent and executed suspected conspirators without trial. Campaign spending exploded, pumping so much money into the economy that Rome’s interest rate briefly doubled. Religion devolved from a unifying force to a political tool, as politicians increasingly claimed the sanction of gods and omens to delay elections and block unfavorable laws.

It would be too facile to draw a direct causal line between each of these events. But they all took place within an atmosphere of deepening distrust and loss of faith, in which each breach made the next more likely. The political scientist Robert Dahl argued that self-government is most stable where societies develop a “system of mutual security”: where conflict is confined to a finite battlefield and political actors agree not to use all of the weapons at their disposal. What we see in the last years of the Roman Republic is a system of mutual security falling to pieces. In its last days, as Rome’s leaders met in a final effort to avert civil war, Cato himself scuttled a face-saving deal: As he shouted to the negotiators on his own side of the table, “You’re being deceived again!” The last measure of political trust had leached away.

But it’s not enough to identify these vicious cycles of failing norms. What sets them in motion? Rome’s example suggests at least one cause: These vicious cycles often begin when the stakes of politics increase more rapidly than a political culture can adapt.

The Republic’s consensus-driven institutions were built by and for an elite that enjoyed a rough and hardy equality. The founding republican elites, in a popular shorthand of the time, prayed to clay gods rather than marble ones. Empire changed that: In the judgment of an ancient historian who observed the Romans firsthand, “It is clear that when the state achieves considerable prosperity, lifestyles become more extravagant and men become unduly keen for offices and other objects of ambition.”

Feeding on foreign conquest, power grew more lucrative than it had ever been. A term in office at home was a promise of plunder abroad. That wealth could be turned into the best Greek education for one’s children, into the purchase of political “clients” and hangers-on and into the massive outlays that would secure election again. The growth of the political stakes outpaced the evolution of new norms for a new world: Rome never discovered how to sustainably meld empire abroad and republic at home.

In our time, a norm has held that a president is entitled to have qualified nominees confirmed by the Senate; yet judicial vacancies are at a historic high, and 68 confirmable positions were unfilled at the end of President Barack Obama’s first term. A norm has held that the Senate filibuster protects the rights of the minority in extraordinary circumstances; yet filibuster use has hit all-time record levels, and a 60-vote threshold in the Senate has turned from extraordinary to routine. A norm has held that Congress never threatens a debt default to gain political leverage; yet we have come within days of default twice in the past three years. All of these steps have been legal.

There’s reason to hope that this autumn’s brush with default has strengthened the norm against such threats. As Senate Minority Leader Mitch McConnell (R-Ky.) colorfully put it, “There’s no education in the second kick of a mule.” Similarly, there’s reason to hope that Senate Democrats’ important decision to limit the filibuster will actually shift the supermajority requirement back to its historic role: a gauge to register exceptional opposition, not a chronic choke point on legislation.

But growing scarcity can raise the stakes of political competition, too—and this seems to be the case in our republic. As the conservative commentator David Frum has persuasively argued, “Once it seemed possible to have the spending Democrats wanted, financed at the tax rates the Republicans wanted, while paying for sufficient national security and running bearable deficits. That sense of expansiveness is gone.” Whether the cause is an influx of wealth, or a dawning discovery of scarcity, the effect can be the same. Losing becomes much more costly and far more infuriating—in the first case, because of the fear that opponents will use their wealth to exclude you from power, and in the second case, because of the fear that one more election will put your political priorities permanently out of reach.

And this fear is redoubled whenever politics is seen not simply as a struggle over wealth, but as a struggle over identity. The early Roman Republic prided itself as a society of small landowners who practiced the traditional virtues; the late Republic saw those small farms swallowed up by the plantations of the ascendant elite, a social revolution that added fire to the brutal debates over land reform. And in contrast to the homogeneity of the early days, the late Republic was thrown open to the world, and a tone of cultural paranoia crept into the language of the old guard. We can hear it, for instance, in a letter from Cato’s great-grandfather: “In due course, my son Marcus, I shall explain to you what I found out in Athens about those Greeks….They are a worthless and unruly tribe. Take this as a prophecy: when those folk give us their writings they will corrupt everything. All the more if they send their doctors here.”

The cultural paranoia of the optimates has its echo on today’s American right, in a nation reshaped by immigration and a shrinking white majority. Listen to an evangelical voter asked in a recent focus group to describe the disappearing world he grew up in: “Everybody is happy. Everybody is white. Everybody is middle class, whether or not they really are. Everybody looks that way….Very homogenous.” When politics looks like a question of cultural self-defense, political norms may also look like empty niceties unsuited to the urgency of the times.

We know where this downward spiral takes us. But what can we do to check it? A bit paradoxically, the worst thing we can do in a situation like this is to predict decline and collapse—because such predictions become self-fulfilling.

Rome’s hardliners were certainly born into an unstable state. But long before anyone else—long before it was a reality— they insisted that the Republic was not merely unstable, but falling apart. For more than a decade, Cato made his name as Rome’s prophet of tyranny. Inspired by these fears, the optimates took dramatic, uncompromising action that made collapse more likely.

On the eve of civil war, Cato declared to the Senate, as only a spurned prophet could, “Now these things are come to pass which I foretold to you!” But he failed to consider that doom-mongering is itself a political act: It turns the unthinkable into the acceptable, and justifies radicalism in the name of liberty. Rome’s political leaders broke norms because they believed the Republic was at stake—when the Republic was really in the norms themselves.

The idea that our republic is perpetually one small step away from tyranny is our most dangerous inheritance from the Romans. America’s founders regularly branded their opponents as would-be “Caesars,” and in our time, their style of argument has blended with apocalyptic religion and taken on new life, from Sen. Ted Cruz’s claim that “this is an administration that seems bound and determined to violate every one of our bill of rights,” to Gov. Rick Perry’s argument that implementing Obamacare is “a criminal act,” to Rep. Michele Bachmann’s belief that “we are in God’s end times history.” And while Democrats in the George W. Bush years did not practice obstruction with nearly such apocalyptic gusto, they too suffered their hyperbolic moments (Al Gore’s invocation of the president’s “digital Brown Shirts” comes to mind).

In all, it has become the background drone of our politics, the dull hum of impending doom. Let’s understand why this thinking appeals. Envisioning decline is addictive. It offers us the chance to imagine our times as extraordinary and to cast ourselves in heroic roles to meet them. And the thrill demands a higher dose of doom each year.

But let’s also understand what this thinking does. If our republic is at stake, then it’s reasonable to treat an elected president as illegitimate. If our republic is at stake, then it’s fair to nullify laws that offend us. If our republic is really at stake, then defaulting on our debts to save it—paying any price at all—is a bargain.

To study the Roman Republic’s last years is to watch this pattern play out in a distant mirror. And to study the years of its strength is to come into contact with an entirely different cast of mind. This is the awareness that the norms that grow up over generations of experience embody more wisdom than we know, are worthy of respect for their complexity and their practicality, and, if radically disturbed, will react in unpredictable ways. It’s the calm faith that our times are likely to be no more or less extraordinary than any other times. And it’s the conviction that vigilance is liberty’s price, but paranoia is its solvent. These are all fundamentally conservative insights, and they sit uncomfortably with radicals of any age. The Romans had a name for this cast of mind: mos maiorum, “the way of the elders.”

Rome’s tragedy is that the men who saw and sold themselves as guardians of the way of the elders did more than anyone to undermine it. Our hope is that we have what they lacked: the example of their failure.