Acting as an artform is less about pretending than it is about expressing oneself and projecting and bringing characters to life. Acting as purely pretending is what spies and undercover police do and it's not an artform. The art of acting is not about pretending primarily. Everything an actor puts into a performance is rooted in who they are themselves, in their own personality and nature and identity. An actor's ability to portray a role is limited by who and what they are. As such, it's very important to get actors of the right backgrounds to portray roles. I've seen so many cases of people who are not Irish making a mess of playing Irish characters, and I'm not just talking about accents. Similarly, I've seen many cases of British actors totally screwing up in trying to portray American characters. You said "if one has the ability to portray a role" -I don't think many such people don't have the ability with many roles they take, because they convey the wrong nationality or whatever when playing the role. Addiotionally, it's wrong to take roles that are important to specific ethnic/national groups when one is not a member of the group. That's theft.

totally true Tia...I think we can all agree with you

I disagree.