Wow! Just wow.
The original September Statement with all 624 signatories can be found here.
According to this Daily Nous story, Leiter's lawyers are threatening to sue Carrie and Jonathan Ichikawa-Jenkins as well as the six hundred and twenty four people who publicly supported Carrie, Noelle McAfe, and everyone else who have been publicly and privately subject to Leiter's abusive schtick.
I find it quite troubling that the threats are in Canadian courts. It's pretty clear that by American standards there is no case whatsoever, but to the extent that Canadian law approximates British, then the ability to ruin people's lives with frivolous lawsuits is much higher, because the burden of proof is on the defendent. As a result of this, it's easier to win on cases that would be spurious in the United States, and it's very easy to ruin someone's life even if the case has no chance of winning in Great Britain
Remember what holocaust denier David Iriving managed to do to historian Deborah Lipstadt? Even though she won the case, the British rules made it the case that she had to burn through years and money to avoid jail time. Read the New York Times story about the censoring effect of abuse of British libel law here.
At least twice I know that Leiter publicly bullied people by reminding them that libel law outside of the United States is less forgiving than our own. Once was with respect to Graham Harman, who teaches in Egypt (given what was happening in Egypt at the time, possibly the crappiest thing Leiter has ever done in his role as a public intellectual) and once on the feministphilosophers blog. It's interesting to see this go through.
As Geoffrey Pullum pointed out long ago with reference to a censored Linguistics textbook, British defamation law is not philosophically defensible. Depressing and embarassing if one of our most noted philosophers of law is taking advantage of these standards.
[Shouldn't have to say this, but here goes. Everything above is just my opinion. In U.S. courts at least, this would be dispositive (see Vogel v. Felice, 2005; hat-tip Charles Pence). I hope that Carrie, Jonathan, me, and the other 623 colleagues of Leiter who signed the letter don't have chance to find out with respect to Canadian ones.]