Is it true that our nation's congress governs motivated by fear?

An article in today’s Slate magazine is titled ’‘Why Newtown Wasn’t Enough’’. The subtitle reads says, “Gun control advocates won’t win until senators fear them as much as they fear the NRA.” Politicians campaign on their toughness and ability to inspire courage in the body politic, to take on every enemy, foreign and domestic. But in practice, don’t they all to often model cowardice, voting based on their fears of losing their lucrative seat in the halls of power rather than their moral conviction?

I know there are politicians who oppose expanding background checks, or even favor eliminating the ones we do now. But universal background checks are very heavily supported by the American public. Here’s ample proof of that:
    1 — Polls: Background Checks Have Higher Approval Rating Than Mother Teresa
    2 — Background Checks Beat Apple Pie, Baseball, Kittens In Americans’ Hearts: Poll
    3 — 9 in 10 back universal gun background checks

The problem is that the proponents of running background checks on all gun sales are not organized. They don’t have a multibillion dollar industry funding them. So they aren’t feared and the NRA is. Is this how it has to be? Will the forces who have massive financial interests at stake always get their way?