Sen. Daniel Inouye (D-HI), the President Pro Tempore of the Senate, died of respiratory complications on Monday. He had been hospitalized since early December.
Sen. Inouye, who first served in the U.S. House in 1959 before being elected to the Senate in 1962, was serving his ninth term in office, after winning re-election in 2010 with 75% of the vote.
A winner of the Distinguished Service Cross for Heroism, Inouye lost his right arm in combat during World War II. He later received the Medal of Honor, along with other Japanese-American soldiers, from President Bill Clinton in 2000.
In the 1970s, Sen. Inouye served on the Senate panel investigating the Watergate break-ins and chaired another panel investigating the Iran-Contra affair during the Reagan administration.
As President Pro Tempore, Sen. Inouye was third in line to succeed the president, following the Vice President and the Speaker of the House.
Sen. Inouye was 88 years old.