This movie was over-shadowed by 'The Jackal' (Bruce Willis, Richard Gere) which was released the same year. Having seen both films, I can honestly say this is the superior film.
Granted, the production value of 'The Jackal' was very good, it probably had a substantially bigger budget. However, 'The Assignment' is well written and has a fascinating story. Aiden Quinn is flawless in dual roles. Aiden Quinn and director Christian Duguay did a great job of establishing a deep and multi-layered relationship between the title character and his family. I particularly liked the ending.
I was reminded of the Jack Ryan character in the Tom Clancy movies. Both are Naval officers thrown into unbelievably dangerous roles as they covertly work on behalf of National security. And yet, both Harrison Ford and Aidan Quinn reveal their respective characters as heros who manage to be both virile and gentle. They have a genuine tenderness and vulnerability in their relationships with their families.
What I don't understand is how the opinions of all who have posted on this movie (myself included) can be so much more positive than the luke-warm reception the film has received. This is a movie that has enough complexity and subtlety that it remains compelling after multiple viewings. If you are a fan of espionage-genre films, I recommend 'The Assignment' enthusiastically.