In the 900th issue of Action Comics, Superman decides to go before the United Nations and renounce his U.S. citizenship. " 'Truth, justice and the American way'—it's not enough any more," he despairs. That issue, published in April 2011, is perhaps the most dramatic example of modern comics' descent into political correctness, moral ambiguity and leftist ideology.

We are comic-book artists and comics are our passion. But more important they've inspired and shaped many millions of young Americans. Our fear is that...