Issa formed an exploratory committee to replace fellow Republican Hunter, who is scheduled to be tried in January for allegedly siphoning campaign money for personal use. The committee allows Issa to raise money.
"I have received such a tremendous outpouring of encouragement from supporters inside the district, and around the state and across the Nation," Issa says on his website . "I'm truly grateful for the many encouraging phone calls, messages and letters that I have received."
No one responded to messages left through the website or with Campaign Compliance Group, a company that is managing contributions made through the site. Issa, 65, was widely known to be considering a run, having told The Wall Street Journal that he might seek the seat. The former nine-term congressman announced his retirement before the 2018 election in a neighboring district that he narrowly won two years earlier. That seat flipped parties last year to Mike Levin in an election cycle that raised Democrats' advantage over Republicans in California's congressional delegation to 46-7.
Issa, who enthusiastically backed Donald Trump's presidential bid, was picked last year to lead the U.S. Trade and Development Agency. His appointment has yet to be approved by the Senate. Hunter, 42, is also being challenged by Republican Carl DeMaio, a radio host and former San Diego city councilman with broad name recognition, and Democrat Ammar Campa-Najjar, who came within 3.4 percentage points of unseating Hunter in November.
Issa's entry would make it one of the most closely watched congressional contests in the country, though Republicans have a big advantage in voter registration in California's 50th district, which covers east San Diego County and a small part of southern Riverside County.
Hunter won a sixth term last year, barely two months after he and his wife were charged with using more than $250,000 in campaign funds for personal expenses ranging from groceries to golf trips and family vacations. Margaret Hunter has pleaded guilty to one corruption count and agreed to cooperate with investigators.
The Marine combat veteran, whose father represented the district in Congress for 28 years, has pleaded not guilty and framed the charges as political attack by prosecutors sympathetic to Democrat Hillary Clinton's 2016 presidential bid. U.S. District Judge Thomas Whelan denied Hunter's bid to dismiss the case, which Hunter has appealed.
Whelan delayed Hunter's trial this month Jan. 14 from Sept. 10, to allow the appeal to play out. The postponement forced potential challengers to decide before knowing the outcome of the case because the last day to file as a House candidate for the March primary election is Dec. 6. The San Diego County Republican Party is scheduled to consider an endorsement Oct. 14.
Hunter spokesman Mike Harrison said Thursday that congressman had no intention of relinquishing his seat. Hunter wants to provide his district "with the leadership and commitment to the conservative values and pro-Trump principles which they care about while, at the same time, ensuring that a Bernie Sanders-AOC Democratic socialist does not have the opportunity to advance a horrible, progressive agenda in Congress," said Harrison, referring to U.S. Rep. Alexandria Ocasio-Cortez, a New York Democrat.
Ron Nehring, a former California Republican Party chairman, said Issa endeared himself to many conservatives as chairman of the House Oversight and Government Reform Committee from 2011 to 2015, where he was a vocal advocate for investigations into the Obama administration. His deep pockets would help in a short race.
"This is further confirmation why the political community believes there will be a new congressional representative in that district in 2020," Nehring said. "For Congressman Issa to run, or even contemplate running, is further confirmation that political winds have changed."
Issa's announcement was low-key. When KNSD-TV reported on the website's existence late Wednesday, it was filled with language marked "placeholder." The site was updated Thursday to remove the placeholder language and add links to news stories announcing his move. The site included a biography and instructions on how to send money.
Issa would become one of the wealthiest members of Congress, having made his fortune through a car-alarm company. An exploratory committee does not have to register or file reports as long as its activities are limited to "testing the waters" and it does not engage in campaigning, according to a Federal Elections Commission candidate guide.
Associated Press writers Michael R. Blood and Julie Watson contributed to this report.