The White House has lately assaulted its critics at Fox News – one of the most popular and exuberantly conservative cable news channels. Any media outlet is reluctant to draw attention to another, so the controversy took a while to build, but the fight has now become a matter for debate.

The White House has said that other media companies should stop regarding Fox News as a “news organisation”, as opposed to a mere peddler of opinion. What that advice would mean in practice, or whether it was necessary in the first place, is far from clear.