His sensitivity and alert warmth balance her cool remoteness so perfectly that we’re lulled into thinking there’s nothing more to either of them — and then we see how vulnerable she can be, and how vicious he can be, and how fantastically great they are together when they’re surrendering to their reptilian brains. They don’t seem like abstractions on a page but real people who’ve been married so long and been through so much that they can’t live with or without each other; on a series that’s ultimately less about espionage than marriage, that’s maybe nine tenths of the battle.