When historians of the future try to make sense of the precipitous collapse in American's liberal democratic norms and institutions during our era, they are bound to highlight the rise of Twitter.

I don't just mean because it's hard to imagine the demagogue-charlatan Donald Trump catching on in the way he did without him having access to an instant audience of millions with his Twitter feed. That's important, but not decisive. The same can be said of the army of "propaganda bots" that Farhad Manjoo claims are turning Twitter into a "terrifying scourge on democracy." That's significant, too, but only a part of the story.

Far more fundamental is the way Twitter intensifies and amplifies pathological social tendencies among those who act within, report on, and write about the political world. It turns politicians, political staffers, reporters, editors, pundits, and analysts into petty, vain, childish, showoffy, hostile, vindictive, dogmatic, impulsive, careless versions of their best and most professional selves. This makes Twitter horrible for our politics and equally bad for journalism. The single best thing for both politics and journalism would be for Twitter to go out of business tomorrow.

Would I miss it? You bet I would! Twitter for me is partly a 21st-century teletype machine providing the latest breaking news in real time 24 hours a day; partly an endless, gossipy cocktail party with my peers in the media; and partly an incomparable means of promoting my work and interacting with readers and critics. (If you use Twitter mainly to follow celebrities or communicate with friends, your experience is undoubtedly very different than mine.)

But the news feed, cocktail party, PR outfit, and reader meet-and-greet aren't independent elements of the Twitter experience. They all take place in a context that can best be compared to a high school cafeteria — the largest, most raucous high school cafeteria in human history.

At the center of the room sit the popular crowd — the reporters, editors, and pundits who work for the most prestigious mainstream media outlets in the country. Everyone else in the room wants their approval and attention, including the right-wing trolls seated at the burnout table in the corner, and the geeks who toil away on public policy at universities and think tanks, and more ordinary scribblers like me, who write for slightly lesser-known magazines and websites.

Meanwhile, scattered throughout the boundlessly vast room are the faceless masses, each of them known to various stray people and factions in the cafeteria by their Twitter avatars. These are the most engaged members of our audience, cheering on some, mocking and ridiculing others, sometimes running to this person at that table to "like" and retweet a snarky comment, momentarily elevating him above everyone else. The next minute a different conglomeration of the relatively anonymous lunge over to and encircle some other person at another table, barraging her with abusive "@" tweets that often veer into outright denunciation and personal threats.

And the most popular kid of all — the one many hate but no one ignores — is President Trump.

Like any high school cafeteria, the dynamics are driven primarily by the desperate longing for attention and affirmation. A tweet can say anything. But motivating just about every one, on just about any subject, is precisely the same tacit impulse: "Look at ME!"

Every time it's different. And every time it's exactly the same.

To wit: On Wednesday evening, @realDonaldTrump tweeted an attack on Hillary Clinton's speech from that afternoon. It got liked and retweeted thousands of times in a matter of minutes, no doubt bringing a rare smile to the embattled president's face. A journalist prominently seated at the popular table quickly subtweeted it with a hilariously sardonic remark. Which inspired 100 witty rejoinders — and several troll-table accounts to decry, for the 47th time that day, the "hypocrisy" and "bias" of the "lamestream media."

Now the snark was flowing freely down a million left-hand columns in Tweetdeck, as the various factions in the cafeteria scrambled to devise the next ironic, deflationary comment; the next textbook illustration of the tu quoque fallacy; the next impassioned attack on the president's idiocy — until one of the most popular and polarizing people in the room (Hillary Clinton) tweeted out a lighthearted bit of mockery using Trump's own tweeted (and then deleted) typo from the night before ("covfefe") to make fun of his hostility. Boom! Before you knew it, the Democratic Party's 2016 nominee for president had racked up over half a million "likes" for her tweet, which easily beat the 92,000 or so "likes" for Trump's tweet. That must tell us something!

Or maybe it only tells you who won the cafeteria on the last night of May 2017.

As anyone who makes it out of high school alive knows very well, the cafeteria is not a psychically, emotionally, or intellectually healthy place to be. And neither is Twitter.

Twitter is a place where the desire for approval can motivate people who work in politics and the media to mold themselves into what they think their peers and their audience want them to be, which often means more of what they already are. So a conservative will tend to become more conservative. Same with Trump supporters, with those on the left, and those, like me, who mainly reside in the liberal center. Over time just about everyone ends up becoming further entrenched in their own positions, with persuasion a virtual impossibility.

Twitter is a place where the means of communication vastly intensifies the always-powerful drive for speed in the news business. All news outlets want scoops. Normally a story can't be counted as a scoop until it's been published by a news organization. That can't happen until the story has been verified, checked, confirmed, and edited. But now reporters and other journalists have an incentive and a means of enjoying the professional accolades that accrue to a scoop by tweeting out unverified rumors or retweeting someone else's unconfirmed assertions. And that helps both to spread conspiracies and to advance the nihilistic meme that the media more often than not promotes #fakenews.

Twitter is a place where the emphasis on instantaneous reaction undermines the already-waning ideal of objectivity in the news, as journalists whose published work strives for fairness and balance regularly spout off in reaction to this or that event without a moment's pause of reflection or restraint. (For an especially vivid example of this, look at journalistic reaction to Trump's announcement of American withdrawal from the Paris climate agreement.) This provides media critics (especially on the right) with a constant flood of evidence confirming their charge of all-pervasive ideological bias in "the media."

Twitter is a place, finally, that all-too-often transforms otherwise thoughtful people into a furious mob. This is the phenomenon of "outrage porn" that sweeps through the internet, and especially Twitter, with increasing frequency. We saw it unfold in classic form earlier this week, when comedian Kathy Griffin promoted a stupid and offensive image of herself posing, ISIS-style, with what looked like Trump's severed head. Within hours, Griffin had been eviscerated online, she'd posted a follow-up video containing an abject apology, and her decade-long relationship with CNN had been terminated. Twitter, meanwhile, continued to convulse with indignation — and indignation about those who failed to display sufficient indignation — through the remainder of the week.

This simply isn't how thoughtful citizens of a democracy should be comporting themselves in public.