I recently wrote that Facebook chief executive Mark Zuckerberg is the most powerful unelected man in America. His and the social media giant's efforts to try to combat election-related disinformation on its platform, however comforting, were merely "an admission of a great power that should make Americans uncomfortable", I said.

Some readers argued that I had it wrong. First, criticising the helpful efforts of Silicon Valley is counterproductive at a time when we need all hands on deck, they wrote. Second, I was too narrowly focused on one man. Mr Zuckerberg and Facebook are far from the only powerful entities who could, with a few executive decisions, meaningfully affect the 2020 United States presidential election.