I recently auditioned for a character who is a bad guy and the protagonist of the play. The difficult bit about this is that you cannot play the bad guy as a bad guy. Yes there are times when the bad guy in the show is the one the audiences “love to hate”. The key word there is “hate”. The audiences dislike the bad guy and appreciate that the actor has played a buy guy that the audience loves to hate.
If the character you are creating is the protagonist and is a bad guy, the audience needs to love him. Not love to hate him. William H. Macy is playing a character who is, for arguments sake, a bad guy in Shameless. In an interview with Fresh Air, he said (or I think he said, or will believe he said) you must find a reason to be the hero through the misguided deeds. Find the reason why what you are doing is being the hero.
I don’t mean this to be “I kill people because I believe it is the right thing to do”. Audiences will not buy it. It needs to be something the audience can sympathize with, agree with, believe in. The audience must feel that there is hope of redemption. Otherwise the audience will not like the protagonist. They may love to hate him, but not like him. To be successful, the audience must love your character with all its flaws and misguided beliefs.
Barabbas is a thief and murderer. He does not do it to because he dislikes the Romans. He does it in the hopes that Israel will be freed from Roman tyranny. He hopes that his inspiration and leadership will help the Israelites free themselves from Roman rule. It may not the right path, but it is the path he has chosen.
Through the growing frustration and self doubt, can the audience believe that there is hope for this person. To have the self doubt, the protagonist must find that his path, although for a good cause, is the wrong path. He can still dislike the Romans. He can still try to inspire the Isrealites to freedom. Just not by thievery and murder.