Matt Welch makes official what has been unfolding behind the scenes for a bit: he has left the Los Angeles Times editorial page to return to Reason, with the current title of associate editor and media columnist shown on the website at the libertarian magazine. (More to come on that, probably Tuesday.) His bio at Reason declines to even mention the LAT interlude, where has been assistant editorial page editor since about January '06. At his blog, Matt unveils the change by way of a tagline on an Op-Ed piece in tomorrow's Washington Post.