During a recent interview with Stephen Colbert Will Smith said that he actually discussed the possibility of playing the President and Obama seemed to approve of the role.

Will Smith sat down with Stephen Colbert during the Late Show to promote Suicide Squad and said he actually had a conversation with Obama about playing him in a future role. Obviously the President has a lot on his plate right now (including oh I don't know, running the greatest country on planet Earth) but Obama did say Smith had the ears for the role.

Personally I think there's no other option other than Will Smith. The man is a legend (see what I did there?).