Oscar Isaac, the authentic voice at the center of Coen brothers' new 'Inside Llewyn Davis'

If it were Llewyn Davis doing interviews here at the Ritz-Carlton Georgetown, he'd be late, distracted or desperately looking for an exit. But instead of the fictional '60s folkie he plays in the acclaimed new Coen brothers movie, "Inside Llewyn Davis," Oscar Isaac couldn't be more put together: calm, maybe serene, well groomed, handsome, welcoming and friendly in a way Llewyn would have been suspicious of and cagy about.