jman777- i've been in your situation before, not exactly the same, but in the same category. i found that in some cases there is no possible way other than to just accept it and hope that something happens that will move you and this person away from each other.
i have a question though, are there other people that feel the same way as you do??
if so, there is always strength in numbers, as well as the mob mentality thing. :)
you don't have to be mean to exploit someones weakness, nor do you have to do it in a mean way.
seeing as he is insecure, are the certain things that make him more uneasy than others, if so target those things specifically.
there is also the ole make like you and him are the best of friends, though this could backfire because often people with insecurities will cling to those who "friend" them.
or you can ignore him completely, if this doesn't work, i'd go with rlumley's advice, though a scalpel would be nice it is quite short which means getting within his striking distance. i prefer a blowdart and then the scalpel.
If you have more details about this person, such as his insecurities i'm sure we can find a way to help you.