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 election in history. However, he became more popular over the next few years and defeated D.A. William Raggio, whose 1970 senate campaign began his long political career. Raggio ran for the Nevada Senate in 1972 and won. He then served there for decades to come.