His chance would come soon: He was planning to go to Brussels in April 1953 for a Solvay Conference on proteins and made plans to stop off in England on the way to see the Watson-Crick three-dimensional model and the photos from Wilkins's and Franklin's laboratories.

But anti-Communist sentiments in the U.S. would again interfere with his plans. In late December 1952 a well-known but unreliable informant named Louis Budenz named Pauling as a concealed Communist. Pauling was not a Communist and said so (25 years of FBI investigations have since proved the point), calling Budenz a "professional liar." When Pauling applied for a passport, his old nemesis Ruth Shipley again recommended denial. He received his passport only after swearing in writing and in her presence that he was not a Communist.