Ruined by a cop out ending

It is a shame that a thought provoking film was let down by a cop out. The film asks what would happen if martial law was declared in a major city and how would law enforcement agencies cope. The military would clearly have control. To cast Bruce Willis as the villain meant that ultimately he would face justice for overstepping his authority. He is even given dialogue that hints at megalomania " I am the law !".
In such an emergency, he would be given a free hand to deal with terrorism. The film chose to provide a happy ending by having him arrested for murder. Ridiculous!