Twitter might be a soul-destroying wasteland of politicized anger and propaganda, but it's also highly illuminating. Follow an ideologically wide range of accounts and you can watch America's most engaged political actors and informed observers responding to events, describing what they see, and forging a consensus about its meaning in real time. The result is a remarkably vivid ultrasound of the political soul of the nation.

The picture it revealed on Wednesday wasn't pretty.

While the attorney general appeared before the Senate, parrying questions from both sides of the aisle, there was a perfect partisan symmetry to the reaction, with just about everyone left of center unwaveringly convinced Barr was a lying through his teeth about everything he said and doing everything in his power to protect the criminal syndicate led by the president who appointed him. Those who fall right of center perceived a diametrically opposite reality — one in which William Barr had done nothing wrong, was understandably annoyed at the deranged grandstanding of Democrats, and emerged from the questioning with his stellar reputation fully intact. It was a perfect enactment of negative partisanship, with each side's hatred of the other fully shaping its interpretation of events.

We've known for quite a while — and above all since the outcome of the 2016 presidential election — that our politics are hopelessly polarized. But we've never entered a presidential election cycle already so profoundly — so epistemically — divided. I doubt that even the most hardened and cynical among us are fully prepared for the consequences.

As I've recently argued, with President Trump's approval rating stuck permanently below 43 percent, the only way for him to win re-election is for his campaign to persuade an additional 6-7 percent of the electorate to dislike or fear the Democratic nominee more than it dislikes or hates him. If Bernie Sanders, Elizabeth Warren, or another left-leaning nominee prevails in the primaries, this will involve portraying the Democratic standard-bearer as a socialist, with the definition of "socialism" expanded to encompass the culture war.

The message will be: The Democrats want to steal your money, cripple the economy with environmental regulations, give tax revenue to dark-skinned illegal immigrants, open the border to admit more rapists into the country, give voting rights to murderers, take away your doctor, permit women to kill their babies after birth, ban Christians from public life, and force you to allow your children to surgically alter their gender at will. That's what socialism will be defined to mean — with a second Trump term presented as the only thing standing in its way. Don't think it could work? If so, you haven't been paying attention.

But the prospect of Joe Biden winning the nomination requires a different approach. He's one of the most moderate Democrats in the race, and he has a decades-long track record to prove it. Assuming he doesn't repudiate and apologize for all of it in order to run hard to the left, this will at least partially immunize him against the anti-socialist strategy.

Which is why in the event of a Biden victory in the primaries we're likely to see a repeat and radicalization of the 2016 Trump campaign's effort to treat its opponent as thoroughly corrupt.

In Trump's contest with Hillary Clinton, the Republican was greatly aided in his efforts by the long-standing perception on the right that Bill and Hillary Clinton were shady characters involved in murky underhanded dealings the details of which never quite came into focus. This perception then merged with Hillary's foolish (but relatively trivial) decision to use an unsecured server in her home to write and receive work emails while secretary of state. That triggered an FBI investigation that dogged the Clinton campaign through the primaries and then burst back into the news (thanks to the lechery of Anthony Weiner and the ineptitude of FBI Director James Comey) less than two weeks before Election Day.

Yes, Trump was a know-nothing, rabble-rousing racist and misogynist, and sure he had a reputation for flagrant corruption that involved screwing over contractors and clients, as well as financially vulnerable students at a transparent scam called Trump University. But his opponent was, as far as we know, the first major party presidential nominee to run for the nation's highest office while under criminal investigation by federal law enforcement. (Of course the man who labeled her "Crooked Hillary" was also under investigation by the FBI during the campaign, but this wasn't publicly confirmed until after the election.) With Clinton's unfavorable ratings pulled down to within the vicinity of Trump's, the playing field had been leveled and the former first lady, senator, and secretary of state was forced to fight close to an even match with the reality-show star and real estate mogul from Manhattan.

Is Biden as vulnerable as Clinton to accusations of corruption? Well, Trump doesn't have two and a half decades of right-wing Clinton-hatred and -suspicion to draw on and nurture, and so far we know of nothing resembling Hillary's email server scandal. But as The New York Times reports in a long front-page story on Thursday, there might be something worse.

Read the arcane details for yourself — how Biden's son Hunter, after being discharged from the Navy Reserve for cocaine use in February 2014, landed a $50,000/month gig on the board of a Ukrainian energy company (Burisma) owned by an oligarch under investigation by an allegedly crooked prosecutor; and how as vice president Joe Biden threatened in March 2016 to withhold $1 billion in loan guarantees to Ukraine if the government didn't back off. (The prosecutor who had been going after Burisma was eventually dismissed.)

Those parts of the story have long been well known, including the lack of any evidence that Biden (in the words of the Times) "intentionally tried to help his son by pressing for the prosecutor general's dismissal." What's come to light more recently, along with the renewal of the Burisma investigation by a new prosecutor in Ukraine, are insinuations of more intricate ties between the Bidens and Ukrainian businessmen and government officials — some of whom have alleged (but still unclear) connections to Fusion GPS, the firm that initiated the investigation into Trump's ties to Russia and produced a "dossier" that influenced the FBI into opening a counter-intelligence investigation of Trump.

There is as yet little in this web of intrigue and insinuation that concretely implicates Joe Biden in anything unethical, let alone illegal. And the fact that Rudolph Giuliani, the president's personal lawyer, has been loudly calling for further investigation of the issues and people involved is a sure indication of political motives.

Yet the intrigue and insinuation are there — as is the involvement of Hunter Biden with Christopher Heinz, stepson of John Kerry, the former Democratic senator, presidential nominee, and secretary of state. As the Times reports:

Months after his father became vice president, Mr. Biden joined with Christopher Heinz, the stepson of John Kerry, then a senator, and Devon Archer, a Kerry family friend, to create a network of investment and consulting firms ...

Mr. Biden and Mr. Archer pursued business with international entities that had a stake in American foreign policy decisions, sometimes in countries where connections implied political influence and protection. [The New York Times]

How likely is it that an increasingly partisan justice department will decide to open a criminal investigation of all this — of Joe Biden, his son, and other major players in the Obama administration — at some point over the next 18 months?

Exceedingly likely.

Regardless of what such an investigation turns up, Trump-supporting Republicans will immediately conclude that Biden is just as corrupt as Hillary Clinton and the rest of the Democratic establishment. Partisan Democrats will just as quickly decide that the investigation is a politically motivated travesty and rally to Biden's side (or else dump him in favor of one of the other candidates, some of whom will be more vulnerable in the general election to the anti-socialist strategy). Meanwhile, persuadable voters won't know what to think, beyond concluding in disgust that the whole damn system — the politicians and parties no less than the supposedly neutral institutions of federal law enforcement — is corrupt from top to bottom.

The playing field will be leveled, the waters muddied, the potency of Democratic attacks on the president blunted, with the foul stench of corruption hanging over the whole of the presidential contest, and no one on either side possessing the authority, respect, or intact reputation to confirm or dismiss the legitimacy of the charges.

When no consensus can be reached about what is true, truth itself becomes irrelevant to politics. And that is how Trump beats Biden in 2020.

Editor's note: This article was updated after publication to reflect changes to a New York Times report.