This has to be THE most ridiculous movie I have ever seen. From the creators' point of view, if you portray this movie as a potentially realistic thriller, then at least give the audience some credit... Opposing presidents use the CIA-version of IRC-chat to talk to each other in the midst of a mini-nuclear war, helicopters and cars survive a nuclear blast at point blank range, characters travel around the globe at light speed, Israeli's lose a nuke and don't even bother searching for it, and everybody in this movie just seems to be brainless (apart from Mr. Freeman's character, which is probably why he has to die in the first place...)...
I thought the other Jack Ryan movies were a joy to watch, and at least you didn't have to worry about incredible plot holes or disbelief over some of the patriotism, stupidity and truths in the movie, but THE SUM OF ALL FEARS really rocks off the scale. I figured having Mr. Clancy as executive producer on this movie should have helped, but he presumably kept in touch through his AOL Instant Messenger.
My advice: go see this one (but only if you have some money to spare), but use an open mind, and try to think you're smarter than them...
By the way, my rating: 3/10 (I must be in a good mood...)