Kate Maltby is a broadcaster and columnist in the United Kingdom on issues of culture and politics, and a theater critic for The Guardian newspaper. She is also completing a doctorate in Renaissance literature. The views expressed in this commentary are her own. View more opinion articles on CNN.

While America has fixed its eyes on the Democratic debates this week, 20 candidates for the presidential nomination squared off over -- supposedly -- the biggest issues facing the United States. Senators Bernie Sanders and Elizabeth Warren presented healthcare plans; former Vice President Joe Biden and Senator Kamala Harris clashed over criminal justice reform. These are bread-and-butter issues, which matter to every American -- it's right that they were addressed. But as these debates descended into squabbles over stats and Senate procedures, or who did what under President Barack Obama's tenure, deeper, existential questions were left untouched.

During the second debate on Wednesday night, CNN anchor Don Lemon asked briefly about candidates' response to Robert Mueller's appearance before Congress: should action be taken against President Trump on the basis of his report? The answers were technical and political. Everyone had a view on the question of whether President Trump had colluded with Russia in a campaign to spread disinformation during the 2016 election or had obstructed justice in the attempt to uncover such a campaign.

Yet depressing as it may seem, a President's guilt or innocence isn't even the chief question raised by the Mueller hearings. The problem is not merely who helped Russia reshape the American political landscape: the problem is that such a manipulation of America's psyche was possible at all. What did the candidates have to say about that? Distressingly little.

There is no clear public proof of collusion involving Russian influencers and Donald Trump himself. But it is not contested that foreign agents successfully infiltrated the social media systems in which millions of Americans communicate, develop their political identities and nurture their grievances. It is not contested that in the great new age of "information abundance," as social scientists term the social phenomenon of our information overload, we all struggle to detect good information from bad; truth from lies. It is not contested that Americans now get their political messaging from vast information networks that flow across traditional borders with ease. As the information expert Peter Pomerantsev writes in a groundbreaking new book, "This Is Not Propaganda," the end of the Cold War was expected to bring with it the end of government censorship, and with that a marketplace of ideas that would reward intellectual honesty. Instead, the cacophony of the internet has left us more unmoored from truth than ever.

We've all heard, by now, of Russian bot factories and unscrupulous PR firms who run thousands of fake identities to post on Twitter or in the comment sections of newspapers. The Internet Research Agency in St. Petersburg or the peñabots which helped Enrique Peña Nieto take power in Mexico back in 2012 have become celebrity institutions. (As Pomerantsev notes, stories about the Russian state's online power only reinforce its image of strength -- but how else to raise the alarm?) But most of the online activity Pomerantsev describes is far more sophisticated.

The Mexican activist Alberto Escorcia explains to Pomerantsev how "cyborg" trolls deliberately attack and mislead dissident activists in authoritarian states in order to distract them from building up networks with genuine fellow activists. In the Philippines, Pomerantsev describes coordinated swarms of online commentators who bombard critics of President Duterte with death threats until those critics spend all their time learning new security protocols instead of investigating government corruption. ( Maria Ressa , a former CNN bureau chief now on trial -- yet again -- in the Philippines, is one of the heroines of Pomerantsev's book.) If you really want to undermine a political opponent online, find a way to waste their time and wear down their energy.

There have always been liars and hustlers on the internet. What Pomerantsev highlights so crucially is the level of coordination -- professional and corporate in structure -- in what he calls global "disinformation hierarchies."

Such structures don't prevent the most effective disinformation architects from being hyper-local. The Philippines, for example, is a nation with hundreds of different local dialects, each rooted in different regions. One booster for Duterte, interviewed by Pomerantsev, boasts of running Facebook groups in each of these separate dialects, claiming to be discussion boards for local issues. In each of these separate neighborhoods, online discussions would begin about genuine local concerns -- transport, sewage -- and then suddenly, stories about violent drug crime would begin to be posted more frequently. Like Taboola ads , these stories would be identical -- except that on each neighborhood board, the location would be altered to make it seem that the crime wave was local.

So over months and months in the run-up to the Philippines' 2016 election, this political campaigner persuaded viewers that they were engaged in a genuine neighborhood board; that the other personalities online were genuine neighbors; and then that the neighborhood had a genuine drug problem. This is the political equivalent of catfishing. A few months later, Duterte launched his notorious campaign to clamp down hard on drug dealers -- and to suspend civil liberties in the process. Pomerantsev counts the cost in bodies: thousands of Filipino people, shot without trial or process as suspected drug dealers, with the complicity of a population manipulated into paranoid fears of a drug dealer on every street.

JUST WATCHED CNN security analyst sounds the alarm on Trump's pick Replay More Videos ... MUST WATCH CNN security analyst sounds the alarm on Trump's pick 03:47

We see the same processes at work in America when a friendly-looking avatar pops up on a local neighborhood to urge you not to vaccinate your children or suggest that Democratic politicians are pedophiles. They seem to be locals who know your neighborhood, but are they? With the investigations into the 2016 election, Americans began to wake up to these tactics. "Online influence" has entered the journalistic lexicon: on Thursday, CNN reported on a major campaign by the Saudi government to covertly influence opinion on Facebook, while the Guardian reports in the UK on online disinformation campaigns run by Boris Johnson's close ally Lynton Crosby. But as Pomerantsev makes clear, the organizations behind divisive online influence campaigns have been honing these strategies for over a decade in post-Soviet countries like Estonia. Only now has America taken notice.

Every Democratic candidate should have a plan for how to counter disinformation and misinformation in American politics. Pomerantsev's book should be required reading for each of them. The solutions are not simple: as Pomerantsev points out, it's not illegal to tell a lie. (Traditional PR companies have been doing so for years.) Part of the answer lies in civic education. Teach voters to recognize when a new friend they've made over the internet might be a fake, just as we teach children to recognize potential predators. The rise of hyper-localized disinformation can only be countered by stronger local networks to highlight genuine local concerns -- although this is ever harder in an age when many local newspapers are no longer financially viable.

Stay up to date... Sign up for our new newsletter. Join us on Twitter and Facebook

Increasingly, who we read on the internet shapes who we are. That's true for individuals, but it's also true for a nation. Russia catfished the American psyche in the 2016 election. If the Democrats are serious about rebuilding a civic society, they will have to join in the battle for America's online soul.