In the Senate, Cannon was known as a moderate in the Democratic Party. He served as chairman of several committees, including the rules committee and the inaugural arrangements committee. Cannon was nearly defeated for re-election in 1964 by Republican Lieutenant Governor Paul Laxalt in one of the closest elections in history. However, he became more popular over the next few years and won re-election in 1970 with nearly 58% of the vote. In 1976, he faced former U.S. Representative David Towell, who served just one term in the U.S. House of Representatives before losing reelection, then running for the Senate. Cannon won re-election with 63% of the vote, one of his best election performances of his career. He won every county in the state, except for Eureka County, which Towell won with just 51% of the vote.
