Patricia Clarkson steals the show in "House of Cards." Her best moment is in the last episode. She has slipped Claire some Chinese poison; "just don't exceed the dosage, or you can kill someone." Claire has of course (implausibly) used a full bottle on the loathsome Tom Yates (and this shows, emphatically, that "House of Cards" is not a serious drama, and does not want to be; it's a delightful low-rent noir, in the style of "Dressed to Kill," and God bless it for that). Clarkson--"Ms. Davis"--seems to intuit that Claire has used the Chinese extract for nefarious purposes. But of course she can't say that; this is Washington, DC, and Claire is a power broker, THE power broker. So--coolly--Ms. Davis says, "Your husband's liver could fail at any time. I can't do that for you, obviously, but I know some people. I could make some calls." And then she picks up the Chinese extract. "Remember this stuff can be...