[dragonwriter]

> I often wonder if any of this “age of post-truth” stuff would have become popular had the election gone the other way.

That probably depends how and why it went the other way, just like it probably wouldn't have the same degree of currency if Trump had won but there hadn't been a widely-reported on pro-Trump propaganda campaign apparently separate from the official campaign that was being compared to the Russian military propaganda technique referred to in a RAND analysis as the “firehose of falsehoods” even before any actual suggestion of Russian support for Trump or collusion between the campaign and Russia was publicly made.

> But the media got the last election so completely wrong that they have to find a grand theory to explain what happened.

Like many politically convenient narratives, yours only works of you ignore the facts, in this case specifically that the media narrative you suggest was constructed as a necessary explanation for the media’s missed prediction of the election results was prominent in the media in relation to the election as far back as the primary campaign (and actually had been a factor in US political coverage, though prior to the evidence of the propaganda campaign referred to earlier, one whose prominence had faded significantly since the end of the second Bush Administration, since Rove's derisive “reality-based community” comment in 2004.)

[keiferski]

As far as I know, the consequences of any “propaganda campaign” were minor. Assuming they did happen and considering that the election was very close, then sure, an argument could be made that they ultimately determined the election.

But that isn’t your argument, or at least what I’m interpreting to be your argument (your last paragraph is a single run-on sentence and it’s quite hard to understand.)

If the media weren’t completely wrong, they would have predicted a close race. Instead, they overwhelmingly showed Trump losing by a significant margin. Hence my point: the mainstream media messed up, big time, and instead of acknowledging it, they’ve embarked on a campaign to find a nefarious reason for the entirety of the events, when in reality the cause of election results are far more mundane and have more to do with economics.

[dragonwriter]

> As far as I know, the consequences of any “propaganda campaign” were minor

Tracing causality in a single election is basically impossible for phenomena which aren't very similar to those in previous elections for which there is a solid base across many examples with many variations in alternative factors that themselves are well understood to provide controls. But the effects of the campaign aren't what drove the narrative of the post-truth era, it's existence which was a major media story starting fairly early in the campaign, and the absence of any disavowal of it was.

> If the media weren’t completely wrong, they would have predicted a close race

They predicted a race about as close as it was. They also (in many but not all cases) predicted a near certainty of a Clinton victory, because, as 538 pointed out before the election in explaining why their predictions were different and showed a much lower probability of Clinton winning than other media models, many models assumed that any poll-vs-vote differences would be independent between the states, while historically polling error is strongly correlated between the states.

> Hence my point: the mainstream media messed up, big time, and instead of acknowledging it, they’ve embarked on a campaign to find a nefarious reason for the entirety of the events

But, again, this claim doesn't work because (1) the media found the “explanation” before the events, and (2) no one except those trying to discredit the story describes it as explaining “the entirety of events”.

> in reality the cause of election results are far more mundane and have more to do with economics.

This is just as much of a self-serving and fact-ignoring explanation of the “entirety of events” as the propaganda as the narrative you are complaining about would be if anyone offered it for that purpose, the difference between yours and the other one is that no one—not even the center-right Democratic establishment, who has the most to gain from getting people to believe that story—offers the other narrative for that purpose.