As California’s final votes are counted, here’s how the midterms helped Democrats sweep Orange County

Let's go back to 2014. Orange County was reliably red, except for longtime Democratic strongholds in Santa Ana, Anaheim and Garden Grove.

After the 2014 midterm election, Orange County was politically polarized. Democrats and Republicans won their seats by large margins — none of the races were close.

In the 2016 election, the blue began to trickle from Garden Grove and Santa Ana into neighboring cities (most noticeably Irvine and around Laguna Beach), but it wasn't enough to flip any seats. Hillary Clinton, however, won the county, the first Democratic presidential candidate to do so in 80 years.

But after the 2018 midterm elections, those trickles of blue became a wave. Democrats held Districts 46 and 47 while winning every other congressional other seat in the county.

Changing demographics and higher-than-usual voter turnout contributed to Democrats' victories. Registered Republicans are on the decline in Orange County. Every city in the county has shed voters who register as Republicans, while Democrats have added to their ranks.

In District 48, Democrat Harley Rouda defeated 15-term congressman Dana Rohrabacher by seven points. Rouda was aided by a shrinking pool of registered Republicans in the coastal district.

In District 45, incumbent Republican Mimi Walters faced some of the largest drops in registered Republicans in the county. Democrat Katie Porter won almost every precinct in Irvine, one of most populous cities in the county, and ultimately won the district by four points.

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.

In District 39, Democrat Gil Cisneros did not win the majority of votes from Orange County or San Bernardino County. However, he won in Los Angeles County while capturing crucial precincts in Fullerton, Brea and even Yorba Linda, which once had the largest number of Republicans per capita in the state.