American politics have become little more than extreme and reflexive tribalism.

We all sense it: the rise of hyper-partisanship; the denial that those who seek to position themselves above the political fray actually mean it; the claim or insinuation that the very act of such positioning expresses a concealed form of partisanship; the implication that there might not be any nonpartisan position or truth at all, with all efforts to speak for or act in the name of a genuinely common good or objective reality reduced to an underhanded or dishonest striving for power.

You'll find such tribalism on both sides of the political spectrum, but the primary catalyst for the trend is undeniably the president of the United States and the right-wing media complex that defends him, both directly and indirectly (by ceaselessly attacking his political opponents).

This weekend, President Trump tweeted that the team of lawyers working for Special Counsel Robert Mueller is stacked with "hardened Democrats" — the implication being that the president is the victim of a political witch hunt. And in case the implication wasn't clear:

Never mind that Mueller himself is a Republican and has long worked for Republican administrations, or that Trump himself has donated a lot of money to Democrats (including Hillary Clinton) over the years. Apparently none of that matters because politics is a zero-sum game, Trump is now a Republican, and no one who's ever supported the other tribe can be trusted to conduct a fair investigation of his own possible wrongdoing.

That's the logic of tribalism — and though hearing it radiate with such frequency and intensity from the Oval Office is novel and disturbing, its presence in our politics is not. That's because there is a tribal element in all politics. The only question is whether we strive to transcend it or actively encourage it. President Trump obviously concerns himself only with the latter.

The political world is divided into distinct communities: nations, city states, confederations, empires. These entities each seek to advance their own good, and in doing so they sometimes clash with one another. Something analogous happens within these entities, too, with factions competing and jostling for advantage in the quest to win and hold onto power. The character of Polemarchus in Book 1 of Plato's Republic explicitly defends morality in precisely these terms: everything reduces to helping friends and harming enemies. This tribalistic way of looking at the world is perhaps most brutally expressed in organized crime — with groups of gangsters seeking advantage in often violent, ruthless competition with one another.

The remainder of the Republic is in large part an extended response to Polemarchus' tribalism and its troubling implications for morality and human flourishing. Plato's approach to crafting that response ended up being echoed and developed in different ways down through the millennia by philosophers and theologians, all of whom have insisted that tribalism must be overcome by the embrace of something higher or nobler, be it the common good of the community as a whole, trans-political ideals of virtue, God or the universal church, enlightened reason, or humanity itself.

But from the beginning there have also been critics who've doubted these attempts to direct tribal attachments to a broader or more elevated goal. Sophists in ancient times, and cynics like Machiavelli in the modern world, have argued that these so-called higher ideals are merely the means by which the most ruthless of all tribal partisans seek to gain advantage over others tribes by disarming them with noble-sounding claims about their own motives. The smartest response to such elevated talk is for rivals to puncture the high-mindedness and expose their own self-interested aims.

The American constitutional framers offered one possible rejoinder to the cynics. The best way to mitigate against tribalism was to devise a Constitution that would stand above the factional fray in which political actors in all but the rarest of cases remain embroiled. This foundational law would institutionalize a series of rules and incentives that would channel and direct the competing tribes toward public-spirited ends even when at the individual level their motives were more self-interested.

The Progressives of the early 20th century expanded on this approach, advocating the creation of a class of civil servants who would follow rigorously enforced rationalized bureaucratic procedures that, in turn, would direct them toward the achievement of the common good, despite whatever contrary motives or partisan commitments they might entertain in the private dimension of their lives. In the postwar period, media companies (newspapers, magazines, radio and television stations) joined the effort to impose and abide by rules and norms that would ensure public-spirited outcomes.

When such methods of transcending tribalism fall short, one response is to advocate trying harder to do better. Another is to mock the effort and treat the ideals themselves as a sham. For much of our history we've defaulted to the first option. But now one of our two political parties is led by a man who's unwaveringly committed to the second, and he's backed up in his efforts by a right-wing media infrastructure that amplifies his efforts every day.

Without fully grasping the consequences of his words and deeds, President Trump has done more than any previous president to advance a politics of sophistry and cynicism. It's a politics defined by the unrelenting effort to prove that every apparent act of virtue is in fact an example of something lower — of the very tribalism that motivates Trump's every public utterance and act.

If all politics is zero-sum tribalism, then the president's own zero-sum tribalism no longer seems quite so out of line. It can even seem normal. Which is no doubt one reason why he delights in tearing down the norms that call on us to put aside our self-interest, or to view our self-interest as reaching its ultimate fulfillment, in pursuit of the common good.

We dare not lose sight of the fact that this new normal is much lower than the one it replaces. Once we're no longer capable of recognizing that difference, the collapse in higher political ideals that Trump has helped to bring about will have passed beyond the point at which they can be easily repaired. And then all we'll be left with is gangland politics.