Here is an excellent article on the subject. Its to the point and I have been making the same argument for some time. The article is by Ken Berwitz.
-Robin Kelly is Black and liberal-left, while Debbie Halvorson is White and, though far from a right wing conservative, is certainly less liberal/left than Kelly.
-The 2nd district is almost 2/3 Black, and most of the Whites there are reliably liberal/left. Since, with rare exceptions (Steve Cohen's mostly-Black district in Memphis is the only current one I'm aware of), the vast majority of Black voters tend to vote by skin color, and since most White voters of this particular district vote leftward, OF COURSE Kelly predominated.
-The only reason Halvorson had any kind of a chance was that, at one point, it was thought that the Black candidates potentially could split their vote enough for Ms. Halvorson to win with a good deal less than 50%, but more than any other individual opponent. Obviously, however, that did not happen. When Ms. Kelly emerged as the favorite among Black candidates, this race was over.
Knowing this, can you, or anyone else, seriously think the NRA was the difference here? Not a chance. In fact, the NRA barely involved itself in the race.
If the left has to trump a straw man they must know they are not winning the gun fight yet.