Issa served 18 years in Congress before announcing retirement in 2018. His seat went to a Democrat last election.
Darrell Issa, the former combative House Oversight Committee chairman who took on the Obama administration, inched closer to making his political comeback after Super Tuesday.
With all the precincts reporting, Issa had nearly 5,000 more votes than Carl DeMaio, a former San Diego City Councilman, and appeared to secure his name on the general election ballot for California's 50th Congressional district that is currently vacant.
The top two finishers advance to the November election. The Democrat vying for the San Diego County seat, Ammar Campa-Najja, was in first place with 34 percent of the tally and over 42,300 votes.
The Associated Press hadn't yet called the second-place finisher slot yet, but Issa so far had secured more than 30,600 votes (25 percent) compared to DeMaio, with 25,800 votes (21 percent).