When Christopher Nolan announced two years ago that the character Bane would be Batman's nemesis in The Dark Knight Rises, more than a few eyebrows were raised. While the villain has played a prominent role in the caped crusader's comic book canon, he is not nearly so well known as traditional bad guys such as Joker, Penguin or the Riddler. Now, the real reason behind the hulking antagonist's deployment in Nolan's forthcoming superhero blockbuster has been revealed – at least, in the mind of the rightwing US commentator Rush Limbaugh: it's all a thinly veiled attack on Republican presidential nominee Mitt Romney.

According to Limbaugh, who was speaking on his syndicated radio show on Tuesday, "Bane" is designed to get Americans thinking about "Bain" Capital, the investment fund that Romney founded in 1984. The presidential hopeful is currently embroiled in a political spat with Barack Obama's team, who have accused him of being in charge during a period in which the private equity firm made a high number of layoffs at the companies it owned. Romney says he left the firm before the layoffs occurred.

"So this evil villain in the new Batman movie is named Bane. And there's discussion out there as to whether or not this was purposeful and whether or not it will influence voters," said Limbaugh. "A lot of people are going to see the movie. And it's a lot of brain-dead people – entertainment, the pop culture crowd – and they're going to hear Bane in the movie and they're going to associate Bain.

"And the thought is that when they're going to start paying attention to the campaign later in the year and Obama and the Democrats keep talking about Bain, not Bain Capital but Romney and Bain, that these people will start thinking back to the Batman movies: 'Oh yeah, I know who that is!'"

Back in reality, Bane was not invented by Nolan for The Dark Knight Rises but first rose to prominence in the 1993 Batman comic book series Knightfall, in which he breaks Bruce Wayne's back. Unless the British director had the ability to see into the future in 2010 when he was finalising his plans for the new film, it seems unlikely that he decided on utilising the villain for political reasons. Then again, Nolan began his superhero trilogy with 2005's Batman Begins, featuring a sinister organisation named The League of Shadows, known for manipulating events in order to forge the future in its own image.

Bloggers, including the Guardian's Catherine Shoard, have suggested a rather different political thread running throughout The Dark Knight Rises, with Bane and his "Occupy Gotham" army cast as the 99% and Wayne's battling Batman the capitalist, "radically conservative" antagonist.