U.S. Rep. Mazie Hirono is stepping down from the Ethics Committee in the House of Representatives. 

The congresswoman told House Speaker John Boehner of her resignation in a letter Thursday. She says he’s already informed Ethics Committee Chair Rep. Jo Bonner and Rep. Linda Sanchez, the ranking member of the committee, of her intentions. 

In May, Hirono announced her candidacy to succeed U.S. Sen. Daniel K. Akaka, who is retiring at the end of his term. 

She’s competing for the seat against former U.S. Rep. Ed Case in the Democratic primary. Hirono narrowly defeated Case in the Democratic primary for the 2002 governor’s race, but she later lost to Republican Linda Lingle.