Eastsidekate emails (which I'm sharing with her permission):
This is a nice piece from Samantha Allen on how the e-mail dump revealed that Hillary is a total monster.When this rule was first enacted, Eastsidekate wrote about it here: "Since We're Such Good Friends."
(tl;dr A trans woman in Illinois was able to start her own business as a result of the passport rule, and she wrote a letter of thanks to head of IL's office of Civil Rights. Eventually, it was forwarded to Clinton, who signaled her intent to respond in person, because that's the sort of bullshit she does.)
The passport rule doesn't get a lot of attention, despite being a big deal for the trans community, because most cis people don't understand what a big deal it actually is.
Allen's piece does a good job of explaining exactly why it matters so much.
[H/T the Clinton campaign.]