There is a scene where Jack Stanton is campaigning in Manchester, New Hampshire. He is shown talking with a counter clerk in a "Krispy Kremes" donut shop. There is no Krispy Kreme shop in Manchester, or even in New Hampshire. This is a southern chain, even though its donuts are now distributed throughout the U.S.
When the original novel was published, the author was identified as "Anonymous." As a result of curious professors and investigative journalists trying to identify the author, the person was identified as Joe Klein, an American magazine columnist who was working for the newsmagazine Newsweek. Investigators had shown that the writing style found in "Primary Colors" is identical to the writing style found in Klein's Newsweek articles.