(CNN) With Justice Anthony Kennedy's retirement from the Supreme Court, the America of 1950 is now positioned to write the legal rules for the America of 2050.
That may slightly overstate the likely longevity of the five-member conservative Supreme Court majority that will lock into place if and when the Senate approves President Donald Trump's nominee to replace Kennedy. But potentially for decades, the court could be controlled by justices nominated and confirmed by a Republican electoral coalition rooted in the parts of the country least touched by the seismic economic, cultural and demographic changes reshaping 21st-century America.
That points to a widening gap between the ideological perspective dominant on the court and the lived daily reality for a growing share of the country. In the past -- as in the 1850s with slavery or in the 1930s with the New Deal -- that disjunction has proved an explosive combination in American politics.
"If you want a metaphor, in the scenario you are talking about, it is like two tectonic plates that are locked and trying to move in opposite directions," says William Galston, a senior fellow at the Brookings Institution who's the author of the new book "Anti-Pluralism: The Populist Threat to Liberal Democracy."
Almost always, the Supreme Court is a lagging indicator of the relative standing between the two parties. Because justices serve for many years, it is not unusual for the court's composition to bear the imprint of presidents and Senate majorities that governed years, if not decades, earlier. Kennedy, for instance, was confirmed during the Ronald Reagan administration, before the youngest voters in the past three presidential elections were born.
That doesn't mean the court always lags behind public opinion: At times, as when it banned public school segregation in Brown v. Board of Education or more recently legalized gay marriage, the court has moved faster than, or at least paced, shifts in public attitudes. But the court is always backward looking in the sense that its balance of power is inexorably linked to the choices that voters made in presidential and Senate races years before. And that frequently provokes frustration, particularly when a court majority forged in an earlier era blocks the agenda of a party ascending in a later one.
That was the case in the 1850s, when the Supreme Court led by Chief Justice Roger Taney favored the interests of Southern slaveholding states. That outraged the new Republican Party, which was rapidly growing into the nation's dominant electoral force as the voice of voters in the industrializing North who opposed slavery's expansion. That conflict peaked with the court's Dred Scott decision in 1857, which threatened to allow slavery in all of the territories.
At that point seven of the court's nine members had been appointed by pro-Southern Democratic presidents, who had dominated American politics from Andrew Jackson (who appointed Taney) through Abraham Lincoln's election in 1860. After the Civil War, the GOP, as the nation's predominant electoral force, then pushed through the 13th and 14th amendments to the Constitution, which meant to expunge the legacy of slavery (though they did not eliminate racial discrimination) and confirmed onto the court generations of Republican justices who provided the legal framework for the same forces of industrialization and economic consolidation that the party promoted in its policy agenda.
Something similar recurred in the 1930s, when the Supreme Court struck down a succession of "New Deal" measures from Franklin Roosevelt that expanded the role of government to respond to the Depression. (That process peaked with the Schechter Poultry decision in 1935, which invalidated FDR's National Recovery Administration, the centerpiece of his initial economic program).
At that point, seven of the nine justices had been appointed by Republican presidents, reflecting their dominance of national politics from 1896 through Roosevelt's first election in 1932. (Chief Justice Charles Evan Hughes, appointed by Herbert Hoover, had even been the GOP presidential nominee in 1916.) Roosevelt responded by threatening to expand the court's size, and while Congress didn't approve his effort, enough justices shifted their perspectives (and then retired) to tip the court's balance. As Democrats controlled Congress and the White House for most of the years between 1932 and 1968, a liberal court majority followed their tracks, both expanding individual rights and blessing a more expansive role for government.
It's far from clear, of course, that Democrats in the decades ahead can achieve anything like the political dominance that Republicans did after the Civil War or FDR Democrats did after the Depression. The more precise parallel is that a lasting Republican-majority court today, like those earlier court majorities, would reflect perspectives least affected by their era's dominant social and economic changes (in each earlier case successive waves of urbanization, immigration and industrialization.)
That's critical because from access to abortion, gun rights and gay rights, immigration enforcement (such as last week's decision upholding Trump's travel ban focused on mostly-Muslim nations), religious liberty, voter access and suppression to privacy in the digital age, many of the court's most explosive choices will likely be triggered by America's rapidly evolving social and economic conditions.
A five-member court majority appointed by Republican presidents, and confirmed almost entirely by Republican votes in the Senate, would confront these accelerating changes as the product of a political coalition that remains largely apart from, and often resistant to, this convulsive change. Both at the presidential and Senate level, the GOP relies on what I've called a "coalition of restoration" that primarily revolves around the states, and the voters, least affected by the changes remaking America, whether measured in religious and racial diversity, economic structure or cultural attitude.
Consider religion. White Christians, long a majority of Americans, now represent only about two-fifths of the population, as the nation's increasing religious and ethnic diversity swells the share of non-white Christians and secular adults, according to survey research by the nonpartisan Public Religion Research Institute. But Republicans rely preponderantly on the states, mostly in the Midwest and Great Plains, that least embody this widening religious pluralism. Of the 30 states Trump carried in 2016, white Christians represented 45% or more of the population in 25 of them, according to the annual PRRI American Value Atlas; Hillary Clinton carried just four states with so many white Christians; By contrast, Clinton won 16, and Trump just five, of the states where white Christians represent 44% of the population or less.
Likewise, in the Senate, nearly three-fifths of Republican senators represent just the 20 states where white Christians compose the highest share of the population, while over three-fourths of Democratic senators represent the 30 states with the smallest share of white Christians.
The partisan contrast on immigration is similar. Nationally, the share of America's population born abroad has been steadily rising in recent decades, reaching 13.5%. But that tide has been unevenly distributed, with immigration far less pronounced in many Southern and Rust Belt states. Those states were Trump's base: He won 26 of the 30 states where immigrants represent the smallest share of the population and only four of the 20 where they constitute the highest share. (Those exceptions were Texas, Florida, Georgia and Arizona.) Likewise, the Democratic Senate caucus tilts heavily toward the high-immigration states, while over four-fifths of Senate Republicans represent the 30 states with the least immigrant presence.
The parties are separated just as sharply in their connection to economic change, particularly the transition to an information-based economy. Brookings' Metropolitan Policy Program ranks states based on the share of their total employment that requires high levels of digital skill. Of the 20 states with the largest share of high-digital skills jobs, Clinton won 14 and Trump just six. Trump won 24, and Clinton just six, of the 30 states with the lowest share of highly digital jobs.
In the Senate, Democrats hold fully three-fourths of the seats from the 20 most digitized states; Republicans hold two-thirds from the bottom 30 states. Other census data reinforce this picture. Democrats, remarkably, hold 27 of the 28 Senate seats in the 14 states with the highest share of college graduates in the adult population and 34 of the 42 in the 21 highest. (Cory Gardner of Colorado, who faces a likely difficult re-election in 2020, is the sole Republican senator from the 14 most highly educated states.) Republicans, in turn, control 43 of the 58 Senate seats in the 29 states with the smallest share of college graduates.
Republicans are much more competitive in states that revolve around the blue-collar industries that powered America's economy through most of the 20th century. The GOP, for instance, holds 34 of the 60 Senate seats in the 30 states where the highest percentage of workers is employed in manufacturing, according to the Census Bureau. And Trump won 16 of the 20 states that produce the most oil, 13 of the 16 that produce the most natural gas and 11 of the 15 with meaningful coal production. Those states mostly send Republicans to the Senate as well.
Cultural attitudes follow the same patterns as demographic and economic change. The PRRI surveys track state-by-state attitudes on several large cultural questions. A clear majority of Americans now consistently say abortion should remain legal in all or most cases. But Republicans dominate the Senate seats from the states where the fewest people agree with that sentiment, while Democrats dominate the seats from the states where the most do, according to PRRI findings. The same pattern holds on same-sex marriage, which now also enjoys majority support but still provokes substantial regional variation.
In all these ways, the parts of the country that most resemble the America of the mid-20th century are poised to nominate and confirm the justices who will set the legal framework for the nation well into the mid-21st. The potential tension that could provoke was evident already in the final weeks of the most recent term, when the Republican-appointed justices (including Kennedy) muscled through a succession of party-line 5-4 decisions. Many observers believe that with Kennedy replaced by a more consistently conservative justice, the court could reconsider decisions authorizing legal abortion, same-sex marriage and other socially liberal rulings.
Galston, like some other analysts, believes Chief Justice John Roberts' fear that Americans will see the court as just another front in the partisan wars -- an attitude that some felt influenced his key 2012 vote to uphold the Affordable Care Act -- might mitigate these coming conflicts.
"Roberts thinks institutionally, not just ideologically," says Galston. "He won't lean against that wind all the time, but the ACA was a mighty important example. I think he looked at the possible impact on the political standing and perceived legitimacy of the court and said, 'Wait a minute.' "
Yet those concerns didn't prevent Roberts from joining the 5-4 party-line rulings that rolled out of the court this term as if stamped on an assembly line. The prospect that a lasting Republican court majority will reject more challenges from blue states against conservative federal policies, overturn existing rights like guaranteed access to abortion, slow -- if not reverse -- the expansion of civil rights protections for minority groups, create more religious exemptions from equal rights laws and approve red-state policies that create hurdles to voting -- particularly for minorities -- is certain to create mounting frustration in the country's Democratic-leaning areas. That anxiety would intensify if the Republican-majority court moves to strike down laws and executive actions from the next Democratic president and congressional majority, in 2021 or thereafter.
The coming "court will be in step with the conservatives in the country and out of synch with the liberals, and because we are so divided that court is not going to be a neutral arbiter," says Harvard Law School professor Noah Feldman, author of "Scorpions," a book on FDR's battles with the Supreme Court. "It is going to be a partisan actor on behalf of the conservatives."
Behind their "coalition of transformation" centered on groups that are growing in society -- millennials, minorities and college-educated whites -- Democrats have won the popular vote in six of the past seven presidential elections, a feat unmatched in modern American political history. Yet they have captured the Electoral College and the White House in only four of those races, and, largely as a result, now face the prospect that Republicans will control the Supreme Court for years, no matter how often a majority of Americans support Democrats in presidential contests.
It's difficult to predict exactly how the tension might erupt over a divergence between a court rooted in one political and cultural era, and a majority electoral coalition that reflects another. But one clear lesson of history is that, sooner or later, it will erupt.