Kamala Harris’ campaign for the Democratic presidential nomination rests on a political theory that depends on California’s early primary.

Because California is early, the theory goes, Harris has a path to the nomination if she wins an early primary—South Carolina being the focus. Then she heads West, where she can win Nevada, which is full of Californians, and then breaks out big with a victory in her home state.

Sounds good? Maybe on its face. But dig a little deeper, and there is a significant problem with this theory: Kamala Harris can’t win the California primary.

I don’t mean she can’t get the most votes in a California primary. Of course, she could. But victories in politics are about meeting and beating expectations.

Kamala Harris can’t beat expectations in California.

As the home state senator, she has to do more than win here. She must crush everyone in her path—huge majorities. And that won’t happen for a couple reasons.

First, Harris isn’t that popular in California. Indeed, she’s not even especially well-known, given Californians’ relatively low interest in politics and the fact that Harris has only been a U.S. senator for two years. She has plenty of liberal critics in the state, and she has run behind other Democratic candidates on statewide ballots.

Second, the early California primary actually works against her. Other big-name candidates—perhaps Joe Biden or Bernie Sanders or Elizabeth Warren—will likely still be in the race at such an early time. They have name recognition and followings in California. A lesser known candidate or two could break through after winning Iowa or New Hampshire.

Harris’ candidacy is actually most likely to die in California. One of the other candidates might beat Harris—and that would probably end her campaign.

And even if she wins, it would be close. And getting a majority of the votes in a still-crowded field would be hard. A weak win at home would play like a loss.

So should she skip the primary? That’s what the fictional president played by Martin Sheen did in TV’s The West Wing; he was from New Hampshire so he didn’t run in the New Hampshire primary, because he couldn’t win it.

But California is so big and comes so early that skipping the primary isn’t really an option. California’s primary thus isn’t an advantage for Harris. It might be the foremost obstacle to her candidacy.