Tuesday’s midterm elections were much more than a national repudiation of President Trump, a reminder that the president is still strong in red states or a return to the divided government that Americans so often favor. They were a sign of the political nightmare that will define a generation of millennial politics.

The Democrats took the House thanks to an anti-Trump surge not just among traditional Democratic groups such as minority voters, but also among college-educated people, particularly women, in America’s sprawling suburbs. Republicans expanded their Senate majority as they ran up the score in red states such as Indiana, Missouri and North Dakota. Democratic incumbents lost big in each of these states. The immediate conclusion is that Trump has effectively divided and inflamed the country, pushing more urbane suburban types away from “the stupid party,” to quote former Louisiana governor Bobby Jindal (R), yet driving rural and less educated voters to the polls by appealing to fear and prejudice.

But there is a trend at work bigger than the president. The nation is diversifying. Its cities are growing. Its coasts are increasingly vibrant, diverse and open to the world. These values better fit educated suburbanites than Trump’s xenophobia. These facts suggest that the Democratic coalition is likely to win more votes nationwide, as it has in every presidential election but one since 1992. Virginia, whose northern suburban districts turned the state from red to purple to blue over just a decade, is a harbinger. Given time, as electoral votes and congressional seats shift to these areas, the House and presidential elections are likely to be the Democrats’ to lose. Tuesday’s results are an early indication of this shift.

But the Senate is different. The chamber was never meant to reflect the will of the American majority, and it increasingly will not. In the past, Democrats and Republicans regularly won Senate seats in states usually associated with the other party, creating a centrist power bloc that could bridge partisan divides and promote legislative compromise. This era is ending. Republican tribalists will not suffer a Heidi Heitkamp (N.D.) or a Joe Donnelly (Ind.) representing their states, no matter how centrist their records. Both lost, and by unexpectedly wide margins. The survival of West Virginia Democrat Joe Manchin III and Montana Democrat Jon Tester look like ever-rarer aberrations.

Democrats will eventually pick off Senate seats that Republicans still hold in bluer territories, such as Susan Collins’s seat in Maine. But for electoral purposes, Republican voters are much more efficiently distributed across the country. No matter how many people vote in California, they still get only two senators, the same as tiny Idaho, South Dakota and Wyoming.

The Founders imagined that the Senate would check and cool the impulses of the majority. But the body is poised to serve as a reactionary rural veto on a center-left country, routinely thwarting efforts to address major issues such as immigration, climate change, the national debt, health care, international cooperation and wealth inequality. Staffing the government and the courts could become impossible, as GOP senators refuse to approve Democratic appointees. The judiciary could become more politicized and even more conservative. The United States could fail to compete in providing the sort of modern, competent and responsive government that fosters economic prosperity and attracts foreign talent and investment, unless Republicans start electing moderates who will compromise with Democrats. With the increasing geographic and identity-based divisions in the country, it is more likely that Republican voters will prefer candidates who will promise to take nothing over a compromise.

My elementary school teachers taught me and my fellow children, succored as we were on multicultural urbanism while growing up in Los Angeles, that we benefited from a symbiotic relationship with the rural Americans who grew our food, watched over our nation’s vast open spaces and defined so much of the American experience for so long. We, by contrast, provided a market for their products, connected them to the rest of the world and provided the economic innovation that underpinned national progress. Neither could exist without the other, and both deserve respect.

Increasingly, the relationship will not be defined by respect, but by resentment. The result will be a toxic stalemate.

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