Sudoers' file not working

A couple of weeks ago, I posted about the sudoers’ file , and how there was a special tool for editing it since breaking it is a bad idea, and that in fact I needn’t bother, since I can just add my user to the sudoers’ group with:

usermod -a -G sudo ian

That worked (on Unbuntu) since /etc/sudoers contained a line saying:

# Allow members of group sudo to execute any command
%sudo	ALL=(ALL:ALL) ALL

I tried the same trick on a fresh Debian install today, and no dice:

I assumed this might mean that the sudoers file is different on Debian than Ubuntu, but no, that same line granting permission to the sudo group is there. My next guess is that I hadn’t correctly added ian to that group. But no, that looks okay.

Yup. Log out, log in…