“Technology has overtaken one of the basic functions you needed political parties for in the past, communication with voters,” he said. “Social media has changed all of that, candidates now have direct access through email, blogs and Twitter,” along with Facebook, Instagram, Snapchat and other platforms.

Two developments in the 2016 campaign provided strong evidence of the vulnerability of democracies in the age of the internet: the alleged effort of the Russian government to secretly intervene on behalf of Trump, and the discovery by internet profiteers of how to monetize the distribution of fake news stories, especially stories damaging to Hillary Clinton.

In an email, Samuel Greene, the director of the Russia Institute at King’s College London, described his “best estimate” of Russian cyber hacking under Putin’s guidance:

Teams of hackers, operating with varying levels of resources and at various distances from the central chain of command, had a lot of license to poke and prod and see what they could come up with. Some of these people found it easier to do certain kinds of things — like break into Podesta’s emails — than they had expected. Having obtained a windfall, they were then given license to push it even further.

The question now is who benefits more from the digital revolution and the ubiquity of social media, the left or the right?

Andreas Jungherr, an expert in social and computer science at the University of Konstanz in Germany, argues that the internet is particularly helpful to opposition movements. He emailed me:

It seems to me this is not a question about ideological placement but more about organizational or movement strategy. As long as I am in opposition, the payoff is higher in investing in digital infrastructure and thereby channeling the activities and enthusiasm of my supporters than when in power. So I would expect a re-emergence of political activity, for example in the form of alternative news sources, on the liberal side in the coming years.

Along parallel lines, Cristian Vaccari, a reader in politics at Royal Holloway, University of London, argued in an email that social media have contributed to the sudden emergence of candidates and parties running the ideological gamut:

By qualitatively expanding the pool of participants, social media may thus be substantially contributing to some of the vivid examples of political disruption that we have witnessed over the past few years across and beyond the Western world: from the spread of protest movements to the sudden rise of new parties such as the Five Star Movement in Italy and Podemos in Spain, from the ascent of populist leaders all across Europe to electoral upheavals such as the Brexit referendum and the surge of Bernie Sanders and Donald Trump in the United States 2016 Presidential elections.

Clay Shirky is a professor in the Interactive Telecommunications Program at N.Y.U. In a 2009 TED talk — the full political significance of which has only become clear over the past eight years — he described some of the implications of the digital revolution:

The internet is the first medium in history that has native support for groups and conversation at the same time. Whereas the phone gave us the one-to-one pattern, and television, radio, magazines, books, gave us the one-to-many pattern, the internet gives us the many-to-many pattern.

Shirky continues:

The second big change is that, as all media gets digitized, the internet also becomes the mode of carriage for all other media, meaning that phone calls migrate to the internet, magazines migrate to the internet, movies migrate to the internet. And that means that every medium is right next door to every other medium. Put another way, media is increasingly less just a source of information, and it is increasingly more a site of coordination, because groups that see or hear or watch or listen to something can now gather around and talk to each other as well.

And the third big change, according to Shirky, is that members of the former audience

can now also be producers and not consumers. Every time a new consumer joins this media landscape a new producer joins as well, because the same equipment — phones, computers — let you consume and produce. It’s as if, when you bought a book, they threw in the printing press for free; it’s like you had a phone that could turn into a radio if you pressed the right buttons.

There is good reason to think that the disruptive forces at work in the United States — as they expand the universe of the politically engaged and open the debate to millions who previously paid little or no attention — may do more to damage the left than strengthen it. In other words, just as the use of negative campaign ads and campaign finance loopholes to channel suspect contributions eventually became routine, so too will be the use of social media to confuse and mislead the electorate.

Of course, this problem goes much deeper than the internet. Sam Greene of King’s College London put it this way in an email: