This makes me feel better about Superman's citizenship

Yes, he is a fictional character, why do you ask? [Link]

In the story in question, Superman is summoned to Camp David, where he is confronted by the president's National Security Advisor. The NSA expresses the administration's extreme irritation with Superman's recent actions -- outraged at the Iranian government's violent oppression of protesters, he flew in and joined the dissidents. There, he simply stood there and allowed his presence to assert his solidarity with their cause -- and his mere presence abated the violence for the duration.

The goernment of Iran, however, was not pleased, stating that Superman -- as not only an American citizen, but as a licensed agent of the United States government (a special status some superheroes in the DC Comics universe hold) -- had committed several acts of war against Iran, and the US was not happy to have to answer for his actions. At that point, Superman realized that he had, indeed, put the US in a very awkward position, and was likely to continue to do so in the future -- so he declared that he would present himself before the United Nations and formally renounce his American citizenship.

In the context of this story, that action was anything but a liberal, anti-American gesture. Indeed, I'd argue it was a very pro-American move, and actually a rather conservative gesture.

One aspect of conservatism is individual freedom, coupled with individual responsibility. Here, Superman is taking responsibility for his actions in Iran, and choosing to give up something of tremendous value to him -- his citizenship -- to spare the US from being held accountable for hi actions. It's not an angry rejection of the US and our ideals (despite his stating "Truth, justice, and the American way -- it's not enough anymore"), but a self-sacrifice for the good of the nation.

In another aspect, the whole storyline can be considered a rejection of the Obama administration's handling of the protests in Iran. Superman didn't fly to Bialya or Qurac (two fictional Mideastern nations based loosely on Libya and Iraq  that DC uses when it needs some Mideastern bad guys or storylines), he flew to Iraq -- where he stood with the same Iranian protesters who President Obama refused to support or aid when they rose up against the Iranian tyrants. Superman did what President Obama refused to do -- and then, when confronted by the administration's representative, refused to submit himself to their judgment and instead removed himself from their authority. Well, their nominal authority -- he's Superman, remember?