In 2016 Republican Darrell Issa held onto District 49, which includes portions of San Diego and Orange counties, by about 1,000 votes. His support was greatest in Orange County, where he won that part of the district by 20%. Issa retired, and Republican Diane Harkey held onto the O.C. portion of the district but at a lower 6.8%. That lowered support in O.C. helped propel Democrat Mike Levin to winning the district this year.

Change in registered Republicans between 2002 and 2018: Dana Point: -10% San Clemente: -10%