100 years ago, the first commercial radio broadcast announced the results of the 1920 election – politics would never be the same

For centuries, people had read politicians' words. On Nov. 2, 1920, the first broadcast from a licensed radio station was broadcasting the results of that year's presidential election.

Radio made it possible to listen to politicians in real-time. It meant that personalities started to matter more; the way their voices sounded made a difference. Their ability to engage and entertain became crucial components.

In 1964, media theorist Marshall McLuhan said that "the medium is the message," meaning that the kind of medium through which a message is transmitted matters more than its content.

For centuries, the primary medium for mass political news was the printed word. Political candidates were expected to participate in a series of debates that were attended by thousands, but millions followed the debates through newspaper accounts. By the 1930s, politicians could address citizens directly through radio. McLuhan described the radio as a "hot" medium because speeches could incite passions.

Once television arrived, the political strategy shifted toward using entertainment to get the attention of voters.

In the 1952 election, the Eisenhower campaign started working with ad agencies and actors to create the candidate's TV personality. An enhanced image became the key to political power.

Today, social media further transforms political discourse from reasoned argument to attention-grabbing images and memes.

McLuhan once said that the politician will be too happy to abdicate in favour of his image because the image will be so much more powerful than he will ever be. Some regard modern politics as a fulfilling of McLuhan's prophecy. Democratic societies that neglect the effects of the new forms of media on the quality of political arguments do so at their own peril.