LOS ANGELES — California’s 33rd Congressional District is one of the most reliably true-blue liberal districts in the entire country — and Sen. Ted Cruz (R-TX) might just win it.

The district — represented for decades by stalwart liberal icon Henry Waxman before his retirement last year — encompasses a significant chunk of Los Angeles County, stretching south from Rancho Palos Verdes up through tony Santa Monica and Beverly Hills and extending even further north into the celebrity enclaves of Malibu, Calabasas and Agoura Hills.

Of the district’s 457,000 registered voters, 43 percent are Democrats and just over 26 percent are Republicans, according to data from the California Secretary of State’s office.

But the fact that fewer voters are registered Republicans lends slightly more significant importance to each Republican vote cast in the 33rd. And each vote could be the winning margin in the California GOP’s winner-takes-all, three-delegates-per-district system.

Organized left-wing opposition to Trump in the 33rd has both emboldened the billionaire’s critics and boosted the resolve of his backers. Last July, hundreds of protesters swarmed the Luxe Hotel in Brentwood while Trump was inside delivering remarks to a group of Hollywood conservatives. And earlier this month, West Hollywood Mayor Lindsey Horvath announced that the New York billionaire would be barred from holding campaign events in the famously liberal city, provoking a protest by Trump supporters.

But Cruz has significant support in the district as well. Like many other Republicans, he has raised large amounts of money from the glitzy district. But unlike most other Republicans, he has also won some high-profile celebrity endorsements to compete with Trump’s — including, perhaps, some he would rather not have had. Transgender icon Caitlin (Bruce) Jenner, a self-declared constitutional conservative, offered in March to be Cruz’s “trans ambassador.”

Away from the spotlight, Cruz may also enjoy strong support from pockets of Republicans who live in the district, who are concentrated in beachfront communities in southwest Los Angeles, such as Rancho Palos Verdes (where Trump owns a golf course).

The limited available California polling data suggest that Cruz tends to do better in communities where Republicans are somewhat competitive, and beachfront Republicans in the state’s 66th Assembly district, which overlaps with the southern portion of the 33rd congressional district, recently elected Republican David Hadley to represent them in Sacramento.

That is why Cruz has a chance to win the 33rd district, even though Trump is still favored to capture a comfortable majority of the state’s 172 GOP delegates.

The race among Democrats will be close enough itself. Presumptive Democratic presidential frontrunner Hillary Clinton will be forced to fend off a strong challenge from insurgent Vermont Sen. Bernie Sanders to come away with a majority of the district’s seven delegates. (California Democrats, like Republicans, assign delegates by congressional district, but do so on the basis of proportional representation, with varying numbers of delegates at stake per district.)

Breitbart California has previously predicted that Clinton will pick up four delegates to Sanders’ three here. That could change, however, as the Vermont senator lost several crucial Northeast primaries this month, including in delegate-rich New York.

Clinton has capitalized masterfully on her relationships with some of the district’s most ardent Democrat contributors, including Steven Spielberg, Haim Saban and Jeffrey Katzenberg. Hollywood power couple George and Amal Clooney hosted Clinton at their Studio City home earlier this month for a pricey fundraiser (though the actor insists the money will be spent on down-ballot Democrats).

Sanders, meanwhile, has stuck to more low-key fundraising events, although he has drawn sizable crowds at public rallies in Los Angeles. Sanders’ message will resonate in the district’s more progressive nooks and crannies, including in Santa Monica and Beverly Hills.

Last week, Sanders opened his first California campaign office in Hollywood — and earlier this month, his campaign began buying what is likely some of the most expensive television advertising in the country in the pricey Los Angeles and San Francisco-area media markets.

Sanders, who has raised records amounts of campaign cash, may be able to afford to match Clinton’s spending in what will be crucial advertising buys in the state’s most populous media market. And while Clinton largely commands the high-dollar Hollywood checks, the size of Sanders’ small-money online donation machine is perhaps unmatched in modern political history.

The Republican battle could be just as fierce. Still, as is the case on the Democrat side, heavy losses for Cruz in earlier Northeast primary states could play a factor, both in CA-33 and across the state. With losses in an additional five primary states on Tuesday, the Texas senator cannot mathematically obtain the 1,237 delegates needed to capture the Republican nomination outright.

Complicating matters even further on the Republican side, Ohio Gov. John Kasich could earn as many as twelve delegates in more moderate districts in San Francisco and Los Angeles. Additionally, recent rumblings suggest that Cruz and Kasich could “team up” to divide the state’s 53 congressional districts between them, with an eye toward preventing Trump from reaching the magic number.

Cruz achieved a small but significant coup late Wednesday in announcing former GOP candidate Carly Fiorina as his running mate in the event he is able to secure the Republican nomination. The move allows Cruz to dominate the entire second day of the upcoming California GOP convention, as the Texas senator will now effectively be represented by two speakers instead of one.

Fiorina will also carry Cruz’s message throughout her home state — including the 33rd, which will be more competitive than many could otherwise have imagined.

Joel B. Pollak contributed to this article.

Follow Daniel Nussbaum on Twitter: @dznussbaum