
"A man doesn't live forever-- a legend does. From the moment he declared war on crime, the Batman knew his story would eventually come to an end. But for each soul he has touched, either as an ally or an enemy, a lover or a friend, an inspiration or an obsession, the life of the Dark Knight-- and its tragic conclusion-- is viewed differently. Now those closest to the Caped Crusader gather for his memorial service. Stories are told, feelings are revealed and tears are shed in a final retrospective of Batman's long and astonishing career. And for those of you who think you know the Dark Knight, prepare to find out you never did" -- dust jacket flap.
There is, admittedly, a precedent within the basic premise of the Batman story itself (and Frank Miller, author of the Dark Knight Returns comic is a noted right-wing libertarian) so in the case of that franchise, Nolan isn't inventing whole-cloth but it's also not something that's limited to just his Dark Knight films
Rewinding to the 1980s.
Reagan was president for two terms, Giuliani was cleaning up the mob using RICO during these time periods. The War on Drugs was raging. Communism was still enemy #1 (See: Rocky IV). It was truly a very right-wing time. For whatever, themes around individuals taking power into their own hands to "Reform" corrupt systems (cities). Like Frank Miller's Sin City, these are absolutely right-wing themes. "Cleaning Corruption" is one of the most conservative motivations from a psychological standpoint.
Others here have mentioned the slate of 80's action movies but it felt like 100% of the culture was heading this direction. Frank Miller's Batman approaches at the time, for example, were strongly echoing similar themes: Vigilante justice in the backdrop of political deterioration. Rambo, Predator, Commando, Total Recall, Scarface.
I think it all started with movies like Dirty Harry and Serpico and then just got more and more extreme leading into the 1980s.
You also cannot leave out Judge Dredd comics. There are similarities between Judge Dredd and RoboCop, I have a hard time believing there was no influence. Judge Dredd also had this magic gun that could do different tricks like shoot through walls etc, lived in a corrupt mega city of the future.
I feel in some ways RoboCop was almost like "Serpico + Dirty Harry if you turn everything up to 1,000." Serpico also had this theme of the good cop who is nearly killed and sent to the hospital due to corrupt system etc.
Frank Miller directly addressed that point in "The Dark Knight" comic series. At one point Superman is remembering a past argument with Batman, and (semi-quote from memory):
"And then you laughed that scary laugh of yours. 'Of course we're criminals', you said. 'We have to be criminals to do what we do.'"
