US Congressman Henry Waxman to retire after 20 terms
Leading Democratic Congressman Henry Waxman has announced his retirement after 40 years in office.
Mr Waxman, who first ran for federal office in 1974, said he would leave Congress at the end of the year.
The California politician formerly chaired the House of Representatives Energy and Commerce Committee and pushed for clean air initiatives.
He also helped craft President Barack Obama's signature healthcare overhaul, the Affordable Care Act or "Obamacare".
"Today, I am announcing that I have run my last campaign. I will not seek re-election to the Congress," Mr Waxman wrote in a statement on Thursday.
The Democrat, who was also a force in the expansion of Medicaid, a federal health programme for poor Americans, lost his committee chair seat in 2011 after Republicans took control of the House.
"Henry will leave behind a legacy as an extraordinary public servant and one of the most accomplished legislators of his or any era," Mr Obama wrote on Thursday in a statement released by the White House.