su/sudo using ssh auth

[Todd C. Miller]

I have resisted doing this because I really think it is pointless.

The only reason sudo authenticates at all is to guard against a
lack of physical security.  Using the ssh agent would not protect
against thins since the passphrase is only entered once.  If you
don't want to enter a password in sudo, just turn off authentication
and rely on whatever method was used to login.

 - todd