From a reader:

Jonah,
I have a colleague who is a nice guy for the most part, but recently has
bought into a lot of these theories. Big into Chomsky and more fringy
stuff. Very much for the gold standard, very much against Woodrow Wilson.
He cites this theory about Saddam pumping money into the euro being the real
reason we invaded, and that our dollar is about to crumble, etc. It’s easy
to dismiss an email, but how do I respond to theories from a friend so off
the wall I don’t even know where to start. I mean, I don’t want to take the
time to refute his long missives line-by-line, but then he says, “I’m still
waiting for your response”. I figure you face more of this than anyone on
the planet, so maybe you can help.

Me: I have no good answers, but I feel your pain.