Surf’s up for California Democrats. Photo-Illustration: Elenarts/Getty Images Plus (Donkey); John Lund/Blend Images/Getty Images (Surf)

Everyone knows how strongly Democratic California is, but it’s amazing how quickly and thoroughly the Donkey Party has monopolized political power in the Golden State.

As recently as 2010, California’s governor, lieutenant governor, and state treasurer were all Republicans. Now Democrats hold every statewide elected office. In 2010 there were 19 Republican U.S. House members in the state. Now there are 14. In 2010 there were 15 Republicans in the State Senate and 32 in the State Assembly. Those numbers are now down to 13 and 25. The losing Republican presidential nominees each won 37 percent of the popular vote in California, in 2008 and 2012. The winning Republican presidential nominee took 31 percent of the vote in California in 2016.

Bad as these trends look for the GOP, they are very likely to get worse this November — possibly a lot worse. In a thorough analysis of California’s political climate, Reid Wilson describes 2018 as a “perfect storm” for Democrats. The term we will soon begin to hear is tsunami, to distinguish California from the Democratic “wave” that’s developing nationally.

As Wilson notes, the few assets Republicans carry into the midterms nationally probably won’t help much in California. The GOP’s signature piece of legislation, the tax bill, is viewed very negatively in California, where it will limit or deny state and local income and property deductions to an estimated 2.5 million taxpayers. And the humming economy is more likely to be credited to California’s own Democratic leadership than to Trump, partly because the state is so large and partly because state leaders have defied Trump’s policies wherever possible.

Trump himself is extremely unpopular in the state:

In California, his numbers threaten to become an anchor that weighs down his own party: Just 28 percent of adults approve of Trump’s job performance, according to a December survey by the Public Policy Institute of California. Just 30 percent told pollsters at the University of California, Berkeley’s Institute of Governmental Studies they approve of Trump.

Two-thirds of independents disapproved of Trump’s performance, and 57 percent of all voters said they strongly disapproved.

Aside from the tax bill’s unique unpopularity in California, Trump has definitely damaged his and his party’s brand in the state with the Interior Department’s recent announcement that the state’s coasts will probably be reopened to offshore drilling in federally controlled waters. There haven’t been any new federal leases for offshore drilling in California since 1984, and the very idea tends to produce strong bipartisan opposition. Inadequate or tardy federal response to California’s horrific wildfires by the Trump administration or the Republican Congress is another big potential problem for the GOP.

Most ominously for Republicans, the state’s top-two primary system, which places the top two finishers in a nonpartisan primary on the ballot in the general election, is very likely to produce a November ballot with no Republicans running for the top two positions, governor and U.S. senator. No prominent Republican appears likely to run against Dianne Feinstein and her Democratic challenger state senate leader Kevin de Leon. And Republicans are divided between Trumpist and “moderate” candidates for governor, neither of whom has much of a chance of getting more votes than Democratic front-runners Gavin Newsom and Antonio Villaraigosa, and might finish behind Democrats John Chiang and Delaine Eastin as well. Having nothing but Democrats at the top of the ballot could be disastrous for Republican turnout, while contributing to what will probably be high levels of Democratic enthusiasm in the state.

The top-of-the-ballot vacuum will add to the many problems of Republican U.S. House members from marginal districts, seven of which were carried by Hillary Clinton in 2016. Two of them (Darrell Issa and Ed Royce) have already announced retirements. Another, Duncan Hunter, who has been fighting ethics allegations, is under pressure to hang it up, and Dana Rohrabacher is perceived as being in deep trouble. Other somewhat stronger incumbents like Mimi Walters and Jeff Denham are being endangered by demographic changes, as Wilson notes:

Walters’s district has grown by 33,000 residents, according to U.S. Census Bureau figures. Of those new residents, 30,000 are nonwhite. The white population actually declined in Royce’s district while the overall population grew by 10,000 residents. In Denham’s district, 17,000 of the 21,000 new residents are nonwhite.

In theory, the top-two system could benefit Republicans in some House races, particularly the open seats where many Democratic candidates could be shut out of the general election while two Republicans sneak into it. But on the other hand, having no incumbent eliminates the guarantee that even one Republican will survive the primary. So there’s no particular reason to believe the election system will give Republicans a break they desperately need. Indeed, California’s move toward a system in which most voters automatically receive mail ballots could erode one remaining GOP advantage: the tendency of Republican-leaning voters to participate at higher rates in non-presidential elections than their Democratic counterparts.

If a Democratic tsunami does develop, it could also reinforce the party’s supermajority control of both chambers of the State Legislature, which has been temporarily endangered by some resignations and one potential recall.

With all these problems, California Republicans are in real danger of becoming a marginal factor as voters become accustomed to Democrats as the natural governing party in the state — particularly if they succumb to the temptation of going Full Trump and spending their time lashing their fellow Californians for being godless hippie terrorist-coddling sanctuary city supporters. Republicans self-destructed in the state once before, in the 1990s, when Pete Wilson identified his party with anti-immigrant policies. If they now become the loud-and-proud “deplorables,” then their exile in the political wilderness could last for a long, long time.