The formula politicians use is this:
For every 1 person we hear from about their concerns, there are 1,000 more people with the same view. When hearing from lobby groups, they look at the organization's official stance and the number of members.
This gives groups like the AARP a HUGE advantage.
Now the fallacy in this ratio of contactors to theoretically like-minded people is that, with a group like the AARP with 20 million members means they are speaking for 20 BILLION like-minded people.
Politicos take that to heart.
So when the NRA...with 5,000,000 dues-paying members says "Yeah, we're good a law that says imported pistols need three manual safties, you can't mail order surplus rifles, and all new firearms sales must go through a Federal Firearm Licensed dealer," the vote-whoring politico thinks it's okay to violate his Oath to uphold the Constitution.
When a ZERO TOLERANCE Second Amendment group such as Gun Owners of America (GOA) or the Second Amendment Foundation (SAF) tells elected politicos "No, stuff it up your arse you totalitarian San Francisco salad tosser!", they look at the memberships of 100k or so then kick them to the curb. After saying some lame shite like...
"Thank-you for taking the time to give me your opinion. While I fully support the Second Amendment and the right to own sporting purposed over/under shotguns, common sense legislation is something everyone (in that big gun lobby group) supports. Your D.C. politico <insert mass stamped signature here>."