I haven't watched the episode in quite some time, but as I recall it, when David and Amy are exploring the West Wing in December of '68, they pass a portrait of a mutton-chopped gent of the 1860s and David solemnly informs his new friend that this is Thaddeus Collins, an ancestor who fought in the Civil War. I realize I'm imputing WAY too much power of recall to the writers but I like to think of Thaddeus as the child Tad grown up and doing his bit during the War Between the States.
She does a very good job when she is intellligent, courageous and aware of the threats she is facing. When she goes into "hysterical" mode it becomes too over the top for me.