Plot hole?
Mrs. Townsend
When Thornill discovers that Townsend's wife has been dead for two years, why didn't he just walk out of the U.N. and go back to the Glen Cove police? The woman declared herself, in front of the police, to be "Mrs. Townsend." And who were these people at her so-called "party"?
Why not just punch the woman in the face, breaking her nose, then she would have to go to the hospital, and the police would have to do a complete investigation, and easily discover this woman was not who she said she was. Townsend would verify that his wife was dead (which the police SHOULD have known anyway), and that the house had been "closed" for the season.
If James Mason (character's name escapes me just now) was so prepared as to have a fake Mrs. Townsend act as if Roger Thornhill were a real person, why did he still take him for George Kaplan. Why would international spy, CIA agent, George Kaplan show up with cops and his mother (!) do defend himself on drunk driving charges????!?!? Hellooooooooo??
Weak.