U.S. Representative Ed Royce, the chairman of the House of Representatives' Foreign Affairs Committee, said on January 8 that he will not run for another term in Congress.
The announcement means Royce's chairmanship of the powerful committee will end when his current congressional term expires at the end of 2018.
As chairman, Royce has helped pass new sanctions on Iran, North Korea, and Russia, and increased pressure on Syria's government while pushing for aid to Ukraine.
Royce said in a statement he wants to focus his last year as foreign affairs chairman "on the urgent threats facing our nation," which he listed as the North Korean and Iranian governments, Russian efforts to "weaponize information to fracture Western democracies," and terrorist threats in Africa and Central Asia.
Royce, a Republican, was first elected in his district in southern California outside Los Angeles in 1992.
While he has easily won reelection every two years since then, Royce was facing one of the most challenging races of his career in congressional elections scheduled for November.
In the 2016 presidential election, Democrat Hillary Clinton led Republican Donald Trump by 8 percentage points in Royce's district, and Democrats believe they have a good chance to win control of the congressional seat there.
If Republicans maintain control of the House in the November elections, Representative Michael McCaul, a Foreign Affairs Committee member who is currently chairman of the House Homeland Security Committee, is seen as a possible new leader of the foreign affairs panel, congressional aides said.
If Democrats were to win control of the House, Representative Eliot Engel, currently the ranking Democrat in foreign affairs, is expected to become chairman.
In a statement, Engel praised Royce, who he said was "a dear friend," for working with Democrats to produce bipartisan legislation over the years.