Casting is an underrated art. There used to be an Academy Award for it, and there probably still should be. We honor actors, but not the people who pick the perfect actor for the role, so that actor doesn't have to act quite so much.
"Downton Abbey" is immaculately cast, and the choice of Elizabeth McGovern to play Cora, the Countess of Grantham, seems especially nuanced and inspired. Cora is an American Jew, a transplant to English nobility, who wears all the status and tradition comfortably without fully buying into it. McGovern herself is a transplant, married to a British director for 22 years, long enough to slip effortlessly into Cora's skin.