This is seriously the most important video of the day.

If you want to understand the trolls on Twitter, why they take a discussion of Trump's insanity and insert screaming tweets about Obama "bringing Zika into the USA" (it's happened), here's why: Fox News has taught them to do that.

It's called "whataboutism" and it's a constant tactic to distract even the person who is doing it from focusing on the actual present problem.

This is Last Week Tonight's last show of the season, and John Oliver dedicates the episode to deconstructing Trump's incompetency and the tools he and his state media and followers use to obfuscate. Via the A.V. Club:

Oliver’s point is that Trump (along with his state media organ, Fox News) routinely employs three easily identifiable, equally reprehensible strategies to advance his loathsome agenda, and turn his critics into tooth-gnashing, stomach-churning basket cases in at the same time. Trump’s M.O. of de-legitimizing the media (“Fake news!”), “Whataboutism” (“But Hillary’s emails!”), and straight-up trolling (literally 90 per cent of what he tweets) is, as Oliver puts it convincingly, an assault against “the very concept of truth.”

Whether because Trump is some secretly savvy evil genius (he’s not), or because he’s a petty, egomaniacal, deeply damaged, bottomlessly needy, horrible little bigot (ding!) is irrelevant, since the overall effect is to keep us off balance reacting to six horrible, bigoted, irrational, ludicrous, or otherwise baffling things before the next one comes babbling out of his maw.

Watch. It's breathtaking.