How to make less STOP chopping long lines by default

The web seems to be full of resources for making less stop wrapping long lines by default and chop them instead. I have the opposite problem. It is chopping be default and I want to make it stop. I want word wrapping turned back on by default, but all I can find are instructions for the other way around. I've tried reversing them, but none of the methods seem to be employed to be reversed.

My problem developed about a month ago and is across a number of systems. I suspect it might actually be my dotfiles somewhere, but for the life of me I can't find it.

• less is not aliased to anything in my shell, it is not a function, nor am I getting some binary other than the system default:

  $ which less
  /usr/bin/less
  

• I am not running with the -S argument:

  $ ps waux | grep less
   caleb     3151  0.0  0.0  13592  1036 pts/14   S+   16:06   0:00 less
  

• I do not have anything set in ~/.lesskey:

  $ cat ~/.lesskey
  cat: /home/caleb/.lesskey: No such file or directory
  

And yet line chopping is turned on everywhere it is instantiated. I have to turn it off with -SEnter every time.

The man page clearly states this is the opposite of the expected behavior:

$ man less
...
    -S or --chop-long-lines
        Causes lines longer than the screen width to be chopped (truncated)
        rather than wrapped.  That is, the portion  of  a  long line that does
        not fit in the screen width is not shown. The default is to wrap long
        lines; that is, display the remainder on the next line.
...

Because it is a default there doesn't seem to be a command line switch to turn this off. Where else could this be getting set so I can find it and eradicate it?