The question of which party can best defy the other’s home-court advantage is most urgent in the House, because the chamber has a much greater chance of switching party control than the Senate. After their apparent success in California, Democrats can come close to retaking the House majority just by sweeping away the last remaining Republicans in otherwise Democratic-leaning states.

The Cook Political Report’s nonpartisan rankings show that many of the Democrats’ top House opportunities are concentrated in blue states; among the seats that Cook rates as toss-ups or leaning toward the Democrats are five in California; three in New Jersey; two each in New York, Illinois, and Minnesota; and one each in Colorado, Virginia, and Washington. Cook rates another five seats in Pennsylvania, which Trump carried by only about 40,000 votes, as toss-ups or Democrat-leaning. Democrats also have a more long-shot chance at 10 GOP-held House seats in Clinton states that the Cook rankings rate as Republican-leaning.

For Democrats, those blue-state seats may be more promising than their comparable openings in otherwise red states (such as the suburban seats around Dallas, Houston, and Atlanta), simply because the overall local environment remains so much more hostile to Trump. “When you try to unpack what does it mean to be a swing district in a blue state versus a swing district in a red state, the extra wind is at our back in our blue states,” argues Jesse Ferguson, a longtime Democratic House strategist. “The entirety of the conversation is about how bad Republicans have become under Trump.”

California offered Republicans their best opportunity to reduce their blue-state risk. But they failed to seize the unique opening the state’s odd primary system presented them. Under that system, the top two finishers in each primary advance to the general election, regardless of party.

That created two big advantages for Republicans. One is that Republicans are usually disproportionately represented in California primaries, because younger and Latino voters, two strong Democratic constituencies, usually turn out at much lower rates compared with their numbers in general elections. Returns from the state’s large absentee-ballot vote suggested that pattern strongly continued Tuesday.

That advantage was reinforced by another: the surge of Democratic candidates whose opposition to Trump inspired them to run. In one sense, that tide measured rising Democratic energy. But, the combination of more Democratic candidates and relatively fewer Democratic voters exposed the party to a very real risk—that it could be shut out of the top two in several competitive congressional districts. The risk was especially concentrated in Orange County, a traditional Republican bastion that’s growing more competitive as it becomes more racially diverse and as the Trump-era GOP drives away more white-collar white professionals. Heading into Tuesday, Democrats feared being excluded in one, two, or even conceivably three Orange County seats.