From The Truth About Guns:

A Congressman must run for re-election every two years. You have to make a two-year investment in educating a targeted Dem about the danger of their gun control advocacy. Even if you fail to knock her out in one election, you’ll have a second opportunity just two years later. Continue the education process through the next two years and two years after that. You will have made her gun control support a constant thorn in her side. That will be a rail she won’t want to touch.