WASHINGTON — Rep. Darrell Issa of California said Wednesday he will not seek re-election, marking the exit of a leading Republican critic of Barack Obama and Hillary Clinton and potentially easing the way for a Democrat to succeed him in November.

Issa built a national profile as the chief congressional antagonist to Obama and his administration during his tenure as ranking member and then chairman of the House Oversight and Government Reform Committee between 2008 and 2015. He later targeted Clinton as she moved toward seeking the presidency over her response to the deadly 2012 terrorist attacks on Americans in Benghazi, Libya.

But Issa’s hold on his San Diego-area district became increasingly tenuous in recent years, and he only barely fended off a Democratic challenger in 2016. National Democrats have put Issa’s district at the top of their target lists for November’s midterms.

In a statement Wednesday, Issa did not give a reason for his departure but reflected on a two-decade political career that included jump-starting the process that led to the 2003 recall of Democratic California Gov. Gray Davis.

“Throughout my service, I worked hard and never lost sight of the people our government is supposed to serve,” he said. “Yet with the support of my family, I have decided that I will not seek reelection in California’s 49th District.”

Issa’s announcement comes two days after another California Republican, Foreign Affairs Committee Chairman Edward Royce, announced his own retirement – leaving a nearby Orange County district amid a strong Democratic push for his ouster. Democrats have generally eyed California seats as a key component on their path back to the House majority.

Issa rocketed to national prominence during his four years as Oversight chairman, during which he mounted aggressive investigations into Obama’s administration that fueled attacks from the growing tea party movement and made him a cable-news stalwart. His targets included ATF “Fast and Furious” operation that was implicated in the death of a Border Patrol agent and allegations of political targeting by the Internal Revenue Service.

In 2012, Issa launched one of the first congressional inquiries into the Benghazi attacks, which resulted in the deaths of two diplomats and two CIA contractors during Clinton’s tenure as secretary of state. The Oversight investigation paved the way for the later appointment of a select committee that continued probing the incident as Clinton pursued her run for president.

Since leaving the chairmanship, Issa has sought to cultivate a more bipartisan profile, working on issues involving immigration and technology. His district consists of parts of San Diego and Orange counties that have a solid GOP constituency, due in part to the Camp Pendleton Marine Corps installation, but that polticial base has eroded as California has moved steadily toward Democrats.

In 2016, Issa won re-election by fewer than 2,000 votes over Democratic challenger Doug Applegate in a race that was unresolved for days. Applegate had announced plans to again challenge Issa, as have several other Democratic candidates.

The nonpartisan Cook Political Report rates California’s 49th congressional district as barely leaning Republican by 1-point and put Issa’s reelection chances as a toss-up.

Without a known quantity like Issa on the ballot, Democrats’ chances should improve. In 2016, the district’s voters preferred Clinton by 8 points over Republican Donald Trump.

The Democratic Congressional Campaign Committee placed field organizers in Issa’s district nearly a near ago, and opened an Orange County office last year aimed at flipping the Issa and Royce seats to Democrats.

Andrew Godinich, a DCCC spokesman, said Democrats are “in a strong position” to claim the seat in November and blamed the Republican legislative agenda for Issa’s retirement. Both the GOP’s health care and tax legislation have been unpopular in California; Issa voted against the tax bill last month after concluding it would hurt his constituents due to the loss of popular individual tax deductions.

“California Republicans clearly see the writing on the wall and realize that their party and its priorities are toxic to their reelection chances in 2018,” Godinich said.

Republicans, meanwhile, say they will benefit from the fight between the Democrats seeking to claim the seat. California does not hold partisan primaries, but rather has a “jungle” primary that sends two candidates of any party to the November general election.

“We look forward to facing whoever limps out of the Democrats’ battle royal: black and blue, and broke,” Rep. Steve Stivers, R-Ohio, the NRCC’s chairman, said in a statement.