WASHINGTON — Janne E. Nolan, an expert on international affairs and arms-control issues who advised politicians and diplomats and lamented the reluctance of skeptics to speak out against policies they believed to be wrong, died on June 26 in Washington. She was 67.

The cause was cancer, said David J. Lane, a former United States diplomat and friend who is now president of the Annenberg Foundation Trust at Sunnylands in California, where world leaders gather to discuss international issues.

Ms. Nolan, who stood out as a woman in a field dominated by men, acquired her expertise through decades of scholarship and membership in numerous research organizations. She held various teaching positions and wrote nine books, including “Tyranny of Consensus: Discourse and Dissent in American National Security Policy” (2013).

By “tyranny of consensus” Ms. Nolan meant a kind of governmental ethos that derives from the unwillingness of officials to voice concerns about a policy that they thought mistaken, or even potentially disastrous, once it had been generally adopted and had acquired its own momentum.