US Representative Alexandria Ocasio-Cortez (2nd L), Democrat of New York, holds a press conference with fellow members of Congress to announce Green New Deal legislation to promote clean energy programs outside the US Capitol in Washington, DC, February 7, 2019.

LOS ANGELES — Republicans are already plotting to retake some of the California congressional seats they lost in 2018 to Democrats, and one of the hot-button issues they're talking about is the Green New Deal.

"These California Democrats can't run on rhetoric anymore, they have to run on their record," said National Republican Congressional Committee spokeswoman Torunn Sinclair. "Supporting socialist policies like the Green New Deal and Medicare for All with no regard for cost or the impact it will have on Californians is irresponsible, and will ultimately cost them their reelection."

Last November, Democrats won a clean sweep of all seven GOP-held congressional districts in California that Democrat Hillary Clinton carried in the 2016 presidential election. The win included four GOP-held seats in Orange County, a traditionally conservative Republican bastion in the southern part of the state.

"Orange County is no longer a 'red' county," said Fred Smoller, a Chapman University political science professor. "That's a tremendous change because of the youth and the Latinos who now make up such a large percentage of the population."

As of this week, at least three Republican congressional candidates have announced plans to unseat California Democrats who flipped GOP House seats in 2018. The state's 2020 primary election will be held in March on Super Tuesday.

Democrats targeted include two U.S. House members from Orange County: Mike Levin of San Juan Capistrano and Katie Porter of Irvine. And GOP challengers are believed to be close to announcing runs in other districts, too.

In February, Levin threw his support behind the Green New Deal, the plan by Democratic Rep. Alexandria Ocasio-Cortez of New York to tackle climate change.

"Climate change is the defining issue of our generation, and we must act now to address this crisis before it is too late," Levin said in February after joining a group of House Democrats in introducing the Green New Deal resolution.

Levin, a former environmental attorney, declined an interview request for this story.

"Mike is very much about the government being the answer to every problem and every challenge," said Republican Brian Maryott, mayor of San Juan Capistrano and a GOP candidate running to unseat Levin in California's 49th Congressional District. "He has voted for the Green New Deal, which is preposterous. And he clearly supports and voted for a nationalized health care system — something I think would be a huge, huge mistake."

Maryott said he's raised almost $100,000 since announcing his candidacy March 5, adding, "we have a long way to go. Ultimately, it's going to take $2.5 million to $3 million to be competitive with Mike next year."

Among other things, the Green New Deal sets a target of "net-zero" greenhouse gases in 10 years.

"The Green New Deal certainly doesn't reflect our community," said Republican Don Sedgwick, a Laguna Hills city council member and small business owner who is running to unseat Porter in California's 45th Congressional District. "I expect that Katie Porter will embrace the Green New Deal, because she's a protege of Elizabeth Warren and very close with Alexandria Ocasio-Cortez and Kamala Harris — and all those folks are proponents of the plan."

Porter's campaign didn't respond to a request for comment.

At a town hall held Feb. 19, though, Porter fielded a question about the Green New Deal resolution. She stopped short of a full endorsement but agreed that "climate change is an urgent issue and requires bold action."

Prior to entering Congress, Porter was a law professor at University of California at Irvine.

Sedgwick, who describes himself as a "family-values" candidate, said he launched his bid for the 45th District a few weeks ago and is confident "we will be able to fund a strong campaign."

Up in the state's agriculture-laden Central Valley, meantime, a Republican who finished third in the 2018 primary has entered the 2020 race to challenge freshman Democratic Congressman Josh Harder in California's 10th Congressional District.

"Here in our district, Josh Harder is very quickly earning the reputation of being the 'AOC of the West Coast,' " said Ted Howze, a Republican challenging Harder in 2020. "That's because he is the face of Medicare for All, socialized medicine, and the Green New Deal."

Howze, a veterinarian who works in the dairy industry, describes the Green New Deal proposal as "an economic killer" and is critical of its message to agriculture about the industry being a climate polluter. According to the Republican, "California farmers are already on the cutting edge of environmental technology."

For his part, Harder has focused more on health-care reform and not the climate issue. The former venture capitalist joined a group of colleagues last month in introducing legislation for Medicare for All. Harder wasn't available for an interview.