WordNet
do a job on
v. destroy completely or make ugly or useless; "The dog did a job on my pillow"; "The semastress did a job on my wedding gown"
Usage examples of "do a job on".
So a man does something in support of that guarantee, and a bunch of know-nothings and professional patriots do a job on him.
Its like having someone do a job on the sole of your foot with a wire brush.