There is no guarantee that the Democrats can put the House in play, even if Mr. Trump’s approval ratings remain as low as they are now or slip further. The Republicans have so many safe seats that they could even survive a so-called wave election like the ones that swept Democrats to power in 2006 and out of power in 2010. The Democrats need 24 seats to retake the House.
But whether the Democrats can do it will come down to places like Orange County, which is more populous than Iowa. Four congressional districts that have at least some territory in the county still have Republican representatives, and all four were carried by Mrs. Clinton.
It’s not much of an exaggeration to say that the road to a Democratic House begins and ends at Laguna Beach.
Darrell Issa, who represents the California coast from southern Orange County almost to La Jolla, is probably the nation’s most vulnerable incumbent. That’s based on factors that tend to predict which districts are likeliest to be competitive — like the result of his last election (he won by just 1 point) and how the district voted in recent presidential contests.
By the same measures, the 24th-most vulnerable Republican is Dana Rohrabacher, whose district is immediately north of Mr. Issa’s — stretching up the Orange County coast from Laguna Beach to Sunset Beach. In between, Ed Royce and Mimi Walters represent the 13th- and 20th-most vulnerable districts.
...From The Orange County Register:
But Orange County is not an outlier. Across the nation, the most vulnerable Republican incumbents among the 50 or so most competitive seats tend to be in relatively well-educated, metropolitan districts with above-average Hispanic populations. It’s the opposite of most of the 2016 presidential battleground states, which were whiter, less educated and far less Hispanic than the country as a whole.