I knew I recognized the name, though, and finally placed it. Joosten also starred as Dolores Landingham, the president's secretary in the first two seasons of West Wing. I loved her character and hated it when she left the show, because she was such a sense of strength and brought so much subtlety to her performance. So as a rather belated memorial, here are two clips from her.
First, a clip from just after her funeral when she talks to Jed about running for reelectiong. Quintessential Landingham.
And then the scene from "In Excelsis Deo" when Mrs. Landingham tells Charlie about her sons. This is a masterpiece in powerfully understated emotion.
What a class act, and what a great actress. RIP, Kathryn.