The only reason they went for Dingle in Michigan is that he is/was very pro gun...a jerk and and an a$$hole, but one of the few democrats pro 2nd amendment. Thats the only criteria they usually use in who they back. Not 100% of the time, but they are a one subject advocate group only...
It still bothers me when someone like Dingle professes to be pro 2A but quits the NRA and sends his membership back which he did during Klintons watch.