Civil War (comics)
Civil War was a large comic book story created by Marvel Comics. The story was the main focus of a seven issue series that started in May 2006 and ended in February 2007. It involved every major Marvel character and a large number of minor ones. Nearly every main Marvel title during this time dealt with this story.
The story was about the United States dealing with an accident during a superhero battle that caused 613 deaths. To prevent this from happening again, the government created the Superhero Registration Act (SRA). This was a law that forced all people with superhuman powers to identify them self to the government. Many superheroes believed this was a good thing and that it would save lives. Others believed it was bad. They felt that if the government knew who they were, they would be in danger of others finding out. They believed that the SRA took away many of their freedoms. This caused the superheros to split into two groups. Those supporting the SRA were led by Iron Man. Those against it were led by Captain America.