To a casual observer of California politics, the big news this past weekend – Sen. Dianne Feinstein being denied her party’s endorsement at a state Democratic convention in San Diego – came as a shock.

It is indeed a jolt, if you haven’t been paying attention to the tectonic shift in America’s nation-state, where all the energy is on the political left – defiantly so. In that regard, the state of California’s Democratic Party mirrors the Democratic minorities in Congress, where fire and brimstone emanate from the likes of Massachusetts Sen. Elizabeth Warren and California Rep. Maxine Waters.

This isn’t to suggest that the Feinstein snub – she needed 60 percent of the delegate support to receive an endorsement; she raked in only 37 percent -- isn’t newsworthy. It just needs to be seen in a larger context, which would include the following:

Where’ve You Been the Past Year? In late spring of 2016, Hillary Clinton and Bernie Sanders brought their duel-to-the-death to California and the state’s June presidential primary. Hillary prevailed in that showdown.

Six months after Clinton lost the presidency, however, California Democrats turned to the business of electing a new state party chair. The options, as was the case in June of 2016, were a candidate representing the established mainstream and an alternative advocating a more populist, progressive line. Again, the mainstream choice prevailed, leaving the left further disgruntled.

The Senate contest featuring Feinstein and California state Senate President Pro Tem Kevin de Leon is Round 3 of this bout -- for the third consecutive year, a litmus test of California’s Democratic orientation.

Feinstein, first elected to the Senate in 1992, is the establishment’s choice. De Leon, responsible for single-payer health care and sanctuary-state legislation in Sacramento, carries the banner of disaffected Berniecrats. Fittingly, for the home of Hollywood, the rift between California Democrats is a preview of coming attractions: when what likely is a crowded Democratic presidential field descends upon the Golden State in early 2020 (more on that later).

Size – and the System – Will Save Feinstein. Politics is a nine-inning game – more so in California thanks to a changed primary system in which the top-two finishers advance to the general election regardless of party affiliation (voters approved the switch in 2010). What this means is that Feinstein can survive the convention snub, or even lose outright to de Leon in the June primary and still advance to the November general election as long as she finishes no worse than second. The absence of any viable Republican in California’s Senate contest all but assures that.

What happens after June’s results? Feinstein will count on a coalition of mainstream Democrats, any Republicans who bother to turn out (there may not be a GOP candidate the governor’s race), plus a bloc of “no party preference” voters who lean Democratic, but not as hard-left as de Leon. That should get Feinstein over the top -- easily, I’d wager.

It’s also worth noting that in California, size matters. Winning a race at the top of the ticket, in a non-presidential year, requires amassing roughly 5 million votes. De Leon will be hard-pressed to reach that sum if he can’t find a way to build beyond his core.

Meanwhile, there’s a more immediate concern for de Leon: money . It’s been hard to come by, given the restraints of federal contribution limits and Feinstein’s long-standing ties with the Democratic donor base and her personal wealth . Unless de Leon can find a few million dollars to invest in sustained advertising, building off the Feinstein snub and a pair of recent labor endorsements , that sound bite of his from the party convention – “real leadership, moral clarity, is always doing the right thing, even when no one is watching” – will appear only a few times, at best, in the dead of the night during “Modern Family” re-runs.

The Old Guard Just Got Older. As I’ve noted before in this space , an oddity of California politics is a youth-obsessed culture overseen by a gerontocracy – the nation’s oldest governor (Jerry Brown soon turns 80) and eldest sitting U.S. senator (Feinstein turns 85 turns this summer).

Ironically, it was an angry state convention crowd in 1990 that first punched Feinstein’s ticket. Running for governor at the time, she stood before a liberal throng and was roundly booed for supporting the death penalty. Her campaign quickly turned the video of that encounter in a television ad, giving birth to the notion of “DiFi the Defiant.”

However, in today’s Democratic politics, Daniel has no business being in the lion’s den. Last summer, Feinstein received a strong pushback when she said this about President Trump: “The question is whether he can learn and change. If so, I believe he can be a good president.” That was a few months after she praised Supreme Court nominee Neil Gorsuch as “impressive” and “a very caring person ... obviously legally very smart.”

Telling Democrats what they don’t want to hear worked for Democrats in the early 1990s, when Bill Clinton was breaking with party orthodoxy over welfare reform and crime and tax cuts. Today, there’s little room for dissent.

If You Thought This Was Bad, Wait Until Two Years From Now. The last serious presidential candidate to hail from California? Try Pete Wilson, who crashed and burned in the summer of 1995.

The Golden State dominated national Republican politics for a three-decade stretch beginning in 1952, with Richard Nixon and Ronald Reagan appearing on a national ticket in seven of nine presidential contests. But since Reagan, the well has gone dry. It’s likely that 2020 changes that dynamic, at least for Democrats.

Sen. Kamala Harris looks every bit a presidential contender, raising money and raising her profile nationwide. Los Angeles Mayor Eric Garcetti likewise is suddenly enthralled by life beyond his state’s border . Add billionaire activist Tom Steyer, whose Trump impeachment crusade over the airwaves and via the Internet is a clever way to captures the names of millions of would-be primary voters. And toss in the winner of this falls governor’s race (most likely Lt. Gov. Gavin Newsom or former L.A. Mayor Antonio Villaraigosa), and that’s at least four California Democrats either jockeying to flip pancakes in New Hampshire or, at the very least, taking part in their party’s national conversation.

And that’s not counting Oprah Winfrey and George Clooney, who also live out here. Multiple favorite sons and daughters would create tremendous pressure in California, as the only way the non-celebrity presidential hopefuls could last until the nomination entails winning the March California primary. Which would mean another round of intraparty squabbling over the Democratic identity in the Golden State.