I am not sure how the influence of the NRA can be held responsible for the police "needing" military gear, considering that police began using military gear as laws restricting gun ownership increased.
Stop it, you're ruining the popular leftist anti-gun narrative! The NRA has to be the responsible boogeyman whenever someone is killed with a gun.
It is worth noting that when it was legal for the common citizen to own automatic firearms, the police were perfectly satisfied to be armed with civilian weaponry.
Three words: War on Drugs. Sure, there were SWAT teams before that, but they were fairly limited to large cities like Los Angeles, and were originally used in response to bank robberies, etc. Ever since the War on Drugs began, it has become pervasive.