The most notorious fake letter in American politics entered the history books on a snowy New Hampshire day in 1972.

Published by the arch-conservative Manchester Union Leader less than two weeks before the New Hampshire primary, the letter alleged that Sen. Edmund S. Muskie (D-Maine), then the front-runner for the Democratic presidential nomination to run against President Richard M. Nixon, had condoned and laughed about use of the derogatory term “Canuck” to describe French-speaking Canadians. Muskie responded to the “Canuck letter” with a display of anger that undermined — and he thought ultimately doomed — his bid for the presidency.

It turned out, however, that he had good reason to be outraged. Before the year was out, The Washington Post revealed that the letter was penned as part of a dirty-tricks campaign. It was organized not by Russian operatives but by Nixon’s Committee to Re-Elect the President and included the bugging of Democratic national headquarters at the Watergate apartment complex.

Mailed with a Deerfield Beach Fla., postmark and written in a childish hand, the letter claimed that an aide made a disparaging reference to “Cannocks” within earshot of Muskie when the candidate appeared at a local drug-treatment center. When the letter writer, who identified himself as Paul Morrison, asked for an explanation of the term, Muskie supposedly laughed and answered: “Come to New England and see.”