But while it is a firmly blue state (that currently only has 14 Republicans serving in the House), California will not be an easy sweep for Democrats. That’s because the state tried to make things a little more fair a few years ago.

Proposition 14

In 2010, a proposition was put on the ballot that would change California’s party primary system to a “top two” or “jungle” primary system. Rather than one candidate from each party advancing to the general election in November, the top two vote-getters—regardless of party affiliation—would face off in the general.

Under the party system, voters who were not registered to a party had to choose a Democratic or Republican ballot in order to vote in the primary. With an increasing percentage of Californians registering with no party preference, then-Gov. Schwarzenegger (himself a moderate Republican) believed that the top-two system would encourage greater turnout amongst this constituency.

The system was intended to be more representative and inclusive and the proposition passed, with just over 53% of the vote. At the time, only Louisiana and Washington used the jungle system. Nebraska also uses it for state elections.

What it means for the 2018 midterms

Like the Republicans did during the 2010 midterms, Democrats across the country are hoping to retake the House this election cycle. But a large part of the national strategy entails taking back at least a few of the Republicans’ 14 seats in California; seven of these districts favored Hillary Clinton in 2016, and Democrats think they can flip them this time around.

On the one hand, this should be fairly easy: California has emerged as one of Trump’s biggest opponents and the state has pushed farther to the left over time. What’s more, several of the most prominent incumbent Republicans (Darrell Issa, Ed Royce, and Ileana Ros-Lehtinen) are not seeking re-election.

But choosing strong Democrats to run against the Republicans will not be smooth sailing, in part because the wave of anti-Trump fervor in California has led to an abnormally large group of Democratic candidates running across the state. In the 14 Republican-held districts, a total of 56 Democrats are running.

Why too many Democrats is a problem

With so many Democrats appearing on the ballot, many now fear that the top-two system will prevent the party from getting the wins it needs. There are a number of possible negative outcomes for the Democrats.

The sheer number of competing candidates could fragment the Democratic vote in such a way that no Democrat gets enough votes to proceed to the general election in November—imagine two Republican candidates appearing on the ballot. Or, if a Democrat does receive enough votes to get into the general election, the party still isn’t in the clear: fragmented Democrat voters could chose a candidate who is too progressive to get general election votes in a moderate district, or one who is too moderate to bring in voters in a progressive area.

Take California’s 49th district for example: Darrell Issa, the incumbent Republican, survived his re-election in 2016 by just over 1,600 votes. After Issa announced he would not be seeking re-election this time around, candidates have jumped at the opportunity to represent the district.

Eight Republicans and four Democrats (and a few third-party candidates) have all thrown their name in the ring. But whereas the Republican party has firmly placed its support behind Assemblyman Rocky Chavez, the Democrats are divided—the state’s Democrat Party didn’t endorse a single candidate. Meanwhile, the Democratic Congressional Campaign Committee has decided to fund attack ads against two of the second-tier GOP candidates, rather than endorse one of the Democrats.

Without a clear frontrunner, there is a not impossible scenario in which two Republicans proceed to the general, locking Democrats out of a district that has turned increasingly blue in recent years.

And the 49th might not even be as bad as a few other districts: the 39th has six Democrats on the ballot, while the 48th has eight.

Depending on Tuesday’s results, we could very well be seeing another statewide election proposition—this one to overturn the top-two primary system in years to come.