Here, allow me:

This isn't just shooting oneself in the foot, man.
This is called planting a landmine and stepping on it.

Reform Party issues first apology of the By-election over the tone
of their FB postings: "We apologise for the recent tone of posts on
our page. We have regrouped our admins and settings." Yesterday, RP
was criticized for referring to opposition supporters who
questioned Kenneth Jeyaretnam's participation in the BE as "vote
riggers".