The 2010 United States Senate election in Hawaii took place on November 2, 2010, concurrently with elections to the United States Senate in other states as well as elections to the United States House of Representatives and various state and local elections. The primary elections were held on September 18, 2010. Incumbent Senator Daniel Inouye, also the President pro tempore, secured the Democratic nomination with over 88 percent of the vote over his sole challenger, businessman Andy Woerner, while former state legislator (and Inouye's 2004 opponent) Campbell Cavasso won the Republican nomination with two-thirds of the primary vote.
Focuses of the campaign included Inouye's seniority and ability to direct federal resources to the state, as well as Cavasso's emphases on change and fiscal responsibility. Polling found Inouye with a large lead, although one poll gave the Democrat a lead of only thirteen points, greatly underestimating his share of the vote. Inouye won re-election to his ninth and final term, with nearly 75 percent of the vote to Cavasso's 21.6 percent. The Senator would not serve out his ninth term, as he died in December 2012 and was replaced by appointed then-Lieutenant governor Brian Schatz.
Hawaii last elected a Republican Senator in 1970, and its current delegation to the United States Congress currently consists entirely of Democrats. Democrats have also won Hawaii's electoral votes in every presidential election since Ronald Reagan's landslide election in 1984. The exceptions at the time were then-Governor Linda Lingle (who was serving her second and final term) and then-U.S. Representative Charles Djou, both of whom are Republicans.
The death of longtime U.S. Senator Robert Byrd allowed Inouye to become the President pro tempore and Chairman of the United States Senate Committee on Appropriations. He made no apologies for bringing home as much federal money as he could, despite Republican insistence that the U.S. government taxed and spent too much, a stance he called a "nice gimmick". The Maui News endorsed his reelection.
Cavasso, the 2004 nominee, won the Republican primary again, and ran on a platform of change, emphasizing the need for a balanced budget. Inouye, who defeated Cavasso in 2004 by 52 percentage points, released TV ads that referred to himself simply as "Dan". The senator was said to be "working" for Hawaii's transportation, high-tech economy, education and other needs.
A Rasmussen Reports poll of 500 likely voters conducted on October 13 gave Inouye only a thirteen-point lead over Cavasso, and found the Republican with a modest lead among independent voters. However, the poll would ultimately miss the final margin by forty percentage points. FiveThirtyEights Nate Silver awarded the Rasmussen poll his "worst poll award", citing it as evidence of the pollster's bias against Democratic candidates and observing that it was, as of November 2010, the largest error of any electoral poll in the Fivethirtyeight databases going back to 1998.
Official campaign websites