Ultimately, he was fighting for freedom which is exactly what the military stands for. In this case, it is freedom of information. While I totally understand that he undermined the government by leaking classified information, he was still providing a service that he felt justified in doing. I think he is a hero for standing up for knowledge.
Bradley Manning is a hero when it comes to whistle blowing and urging for more transparency in the American military. Manning knew he could get in trouble for releasing those documents, but he felt it was important for him to do it anyway. He wanted to get the truth out about how the military targets civilians and kills innocent people and children.
What has he done besides break his sworn oath that can possibly be considered heroic? He turned his back on the military, his country and himself when he broke his word. He should be sentenced to life in prison at the very least to send a clear message to anyone else who decides that they can turn their back on their country.
His main intention may have been to reveal the abuses in the United States government, but his WikiLeaks have put real soldiers and undercover agents in harm's way. The leaked information, although it should have been revealed, was hidden for a major reason. Wars are started over matters like this when the ugly truth has been revealed through a secondary source. Bradley Manning's main intention could have been to start arguments with other countries over these black ops.
Bradley Manning leaked confidential information that was crucial to our nation's security. He put an entire country and its citizens at risk. He clearly had something that needed to be discussed in a more public eye, but he could have gone about it in a more professional and secure way. He disgraced the nation and the military.