There are 16 candidates vying for the seat in California's 49th Congressional District, which includes portions of northern San Diego County and southern Orange County. Despite the district's long history of being a conservative bastion in the southern part of the state, President Donald Trump actually came in second place in Orange County in the 2016 presidential election to Democrat Hillary Clinton and lost by an even bigger margin in San Diego County.
"The election in the district is a referendum on Trump and Issa," said Sherry Bebitch Jeffe, a professor of the practice of public policy communication at the University of Southern California's Sol Price School of Public Policy. Issa, who has been one of Trump's stalwart backers, supported spending money on a border fence but voted no last year to the House tax-cut bill.
Democrats see the race in the 49th District as a chance to pick up a seat in the midterm elections as they wage a nationwide fight to gain back control of the House of Representatives. The Democrats need to grab 23 seats from Republicans to get a majority in the House.
Nearly $15.3 million has been spent so far by candidates and outside groups for the Issa seat, including more than $9.2 million by four top Democrats who hope to prevail in Tuesday's "top-two" primary election. There also are four top Republican challengers that together have raised more than $1.8 million.
"Even before Darrell Issa said he wouldn't run again, a lot of people smelled blood in the water," said Stephen Goggin, a political science lecturer at San Diego State University. "Given it's a relatively wealthy district, a lot of the candidates that came out of the woodwork here have a lot of money and other kinds of financial backers behind them."