In 2016, it's likely that Democrats can withstand an even weaker performance among whites. If demographic change follows its recent trajectory, the minority share of the vote in 2016 will likely rise to 30 percent—up 2 percentage points from 2012. Except for John Kerry in 2004, every Democratic presidential nominee since 1976 has won between 78 and 82 percent of the two-party vote among nonwhite voters.
That means if the minority vote follows its durable trends in both share and performance, the 2016 Republican nominee will need to win almost 63 percent of whites to assemble a national majority. That's roughly equal to the 64 percent of whites that Reagan carried in 1984—en route to the most resounding landslide of modern times. Structural changes since Reagan's day inside the white electorate—shifts from the reliably red blue-collar, married, and religious toward white-collar, single, and secular voters more open to Democrats—make that hill even steeper.
That's not to say Republicans could not climb that peak in 2016, but only to underscore that it's a more difficult ascent than consolidating red states and even picking off a few blue-leaning places in a midterm election. Indeed, if the 2016 Republican nominee wins the same share of whites that polls show the party positioned to capture in the 2014 House races, the Democrat would win the next presidential race—absent meaningful GOP gains with minority voters.
Republicans don't need to look very far back to grasp that truth. In 2010, the exit polls found that Republican House candidates won 60 percent of white voters (for the first time in the history of polling) and the GOP enjoyed the biggest midterm House gain for either party since 1938. Two years later, Romney virtually matched them by taking 59 percent among white voters and didn't come close to retaking the White House. Recognizing that reality, two prominent GOP strategists—Neil Newhouse (Romney's lead pollster) and Glen Bolger—issued a firm warning last week in a Washington Post op-ed: "Winning in a non-presidential-turnout year, when older and white voters make up a larger percentage of the electorate, should convince no one that we've fixed our basic shortfalls with key electoral groups, including minorities and younger voters." Karl Rove, the chief strategist for George W. Bush's two victories, has raised similar red flags.
Geography sends similar caution signs to the GOP. For all of their likely gains this year, Republicans almost certainly won't dislodge any Democratic Senate seats from what I've termed the Blue Wall: the 18 states Democrats have carried in at least the past six consecutive presidential elections. Even in 2010, when a cresting wave helped Republicans take Blue Wall Senate seats in Illinois, Pennsylvania, and Wisconsin, the party could not follow up by capturing those states in the next presidential race. Although Republicans this year have reaffirmed their ability to compete for states at the edge of the modern Democratic map—Colorado, Iowa, New Hampshire—until they show they can break the Democrats' hold on some of the core Blue Wall's 242 Electoral College votes, the GOP will begin the presidential race in a geographic hole. As Newhouse and Bolger wrote, "Republicans were not able to put any Senate races in those Blue Wall states in play. Thus the GOP 'strategy' [for 2016] is essentially to be perfect in purple states—not a game plan with a high probability of success."