"After passing a devastating tax scam and fighting to rip away health care from millions of families, California Republicans clearly see the writing on the wall and realize that their party and its priorities are toxic to their re-election chances in 2018", said Drew Godinich, a spokesman for the Democratic Congressional Campaign Committee.
Issa did not give a reason for his decision not to pursue a tenth term, but it likely had something to do with the daunting reelection challenge before him. National Democrats have put Issa's district at the top of their target lists for November's midterms. He presided over contentious hearings into the attack on the United States embassy in Benghazi, Libya, and on the Internal Revenue Service's targeting of conservative groups.
Early this week, Congressman Ed Royce, chairman of the powerful House Foreign Affairs Committee had also announced his retirement.
Generally described as the richest member of Congress, Issa bankrolled the successful 2003 effort to recall California governor Gray Davis, leading to the election of Arnold Schwarzenegger.
Issa adds to the growing field of Republicans retiring at one of the fastest paces in decades.
Issa had just managed to win in the 2016 general election with just half a percentage point.
Republican Rep. Darrell Issa will retire from Congress in 2018, avoiding a hard campaign fight in a district that has been a primary focus for Democrats in the coming election.
But in 2018, the Democrats' efforts to unseat Issa already began snowballing. He is also chairman of the House Oversight Committee. For a year, hundreds of activists have appeared weekly outside of Issa's office to protest.
Republicans, meanwhile, say they will benefit from the fight between the Democrats seeking to claim the seat.
Yet another Republican congressman is choosing to retire rather than run for reelection, leaving the GOP's hold on the House of Representatives in further peril.