Whatever, I think the book was much better than the movie.
I mean, why did they have to make the cow herds all Texas Militia owned when in the book those bovine creatures have been rustled about by Argentinian commie guerillas? Doesn't make any sense. And what really ticked me off (you don't realize this at first, since "Jack" Ryan doesn't actually appear in the first 30 minutes), what maniac decided that "Jack" was suddenly the nickname of Jacqueline Ryan, the lesbian CIA intern from Boulder? They left out the best part too, would have been such a great scene to see all those paintball-firing robots mowing down the cows. Well, on a more positive note, I liked the scene where Andrea Price flips out and cuts off the head of the Croatian real estate agent.