Reason magazine was founded in 1968 as an American libertarian monthly. People who believe that Reason no longer represents true libertarian ideals have nicknamed it Treason (or tReason) magazine.
 
The Treason magazine nickname has been cited in print since at least January 2008.
 
   
Wikipedia: Reason (magazine)
Reason is a American libertarian monthly magazine published by the Reason Foundation. The magazine has a circulation of around 40,000 and was named one of the 50 best magazines in 2003 and 2004 by the Chicago Tribune.
 
History
Reason was founded in 1968 by Lanny Friedlander as a more-or-less monthly mimeographed publication. In 1970 it was purchased by Robert W. Poole, Jr., Manuel S. Klausner, and Tibor R. Machan, who set it on a more regular publishing schedule. As the monthly print magazine of “free minds and free markets”, it covers politics, culture, and ideas with a mix of news, analysis, commentary, and reviews.
   
Nolan Chart
tReason Magazine goes to the Dark Side
The guardians of libertarian puritanism throw Ron Paul overboard.
by Billy Joe (libertarian)
Saturday, January 12, 2008
 
LewRockwell.com Blog
Beltwaytarians Against Ron Paul
Posted by Karen De Coster on January 22, 2008 08:21 PM
Someone writes: “Isn’t it ironic that stato and treason, hitherto little-known outside of libertarianism, now have much higher profiles: as the anti-Ron Paul think tank, and the anti-Ron Paul magazine?” Too bad the stato institute’s man just dropped out.
 
Yahoo! Groups—LeftLibertarian2
Jesse Walker
Wed Jun 15, 2011 7:14 pm
(...)
If you want to ask a question about “Beltwaytarians” (or “[T]Reason” or “the Stato Institute” or any other brilliant witticisms), send it in.
     
Economic Policy Journal
Friday, August 19, 2011
David Boaz Elevator Talk
(...)
COMMENTS
Brian
August 22, 2011 11:25 AM
You’ve never seen members of Mises/LRC refer to Reason Magazine as “tReason”?
 
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John Hardy Jun 5, 2012 - Mobile - Public
Seriously hardcore libertarians call the Cato institute the “Stato” institute. Reason magazine is called “Treason” magazine.