The escalating confrontation between the parties over the federal budget rests on a fundamental paradox: The Republican majority in the House of Representatives is now more likely than Democrats to represent districts filled with older and lower-income voters who rely on the social programs that the GOP wants to cut.

A much larger share of Republican than Democratic House members represent districts where seniors exceed their share of the national population, census data show. Republicans are also more likely to represent districts where the median income trails the national level, or the proportion of people without health insurance is greater than in the nation overall.

House Republicans, in their ongoing struggle with President Joe Biden over raising the debt ceiling, have signaled they will push for sweeping reductions in domestic social programs, likely including Medicaid and the Affordable Care Act, the principal federal programs providing health care for working-age adults. And while House Republicans appear to have backed away from pursuing reductions in Social Security and Medicare, the conservative Republican Study Committee has set a long-term goal of cutting and partially privatizing both programs.

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The fact that so many House Republicans feel safe advancing these proposals in districts with such extensive economic need testifies to the power of what Ive called the class inversion in American politics: the growing tendency of voters to divide between the parties based on cultural attitudes, rather than class interests. That dynamic has simultaneously allowed House Democrats to gain in more socially liberal, affluent, metropolitan areas and House Republicans to consolidate their hold over more culturally conservative, economically hardscrabble, nonurban areas.

Yesterday, Biden forcefully reiterated his charge that Republicans would shred the safety net at a White House ceremony commemorating the 13th anniversary of Barack Obama signing the ACA into law. An extended battle between House Republicans and Biden this spring and summer over the safety net may test whether any economic argument can allow Democrats to break through the cultural resistance that fortifies Republican control of these downscale districts.

While Republicans have gained in some areas primarily around culturally and racially infused disputes such as those over crime and immigration, a struggle over spending priorities will inevitably highlight that their policies on these bread-and-butter issues remain diametrically opposed to the economic interest of much of their base, Paul Pierson, a political scientist at UC Berkeley and a co-author of Let Them Eat Tweets, told me.

As I reported last week, to understand the social and economic characteristics of the House seats held by each party, Jeffer Giang and Justin Scoggins of the Equity Research Institute at the University of Southern California analyzed five-year summary results through 2020 from the Census Bureaus American Community Survey.

That analysis inverts many traditional assumptions, even within the parties themselves, about whose voters rely on the social safety net. There has been a massive transformation of the coalitions, Manuel Pastor, a sociology professor at USC and the director of the Equity Research Institute, told me.

Democrats, who led the legislative efforts to create Social Security under Franklin D. Roosevelt and Medicare under Lyndon B. Johnson, have long thought of themselves as the party of seniors. But today, Republicans represent 141 of the 215 House districts where adults aged 65 and older exceed their 16 percent share of the national population, while Democrats hold a clear majority of seats in districts with fewer seniors than average, according to the Equity Research Institute analysis.

Republicans now also control most of the House seats in which the median income trails the national level of nearly $65,000 annually. Republicans hold 152 of the 237 seats in that category. Democrats, in turn, hold 128 of the 198 seats where the median income exceeds the national level.

Perhaps most surprisingly, Republicans hold a clear majority of the districts where the share of residents who lack health insurance exceeds the national level of 9 percent. The GOP now holds 110 of those 185 highly uninsured seats. Democrats control 138 of the 250 seats with fewer uninsured than the nation overall.

Equally revealing is to examine what share of each partys total strength in the House these seats represent. From that angle, the parties offer almost mirror-image profiles. About two-thirds of House Republicans represent districts with more seniors than the national level, while about two-thirds of Democrats represent districts with fewer of them. Roughly two-thirds of House Republicans represent districts where the median income lags the national level, while three-fifths of Democrats hold seats where incomes surpass it. Almost exactly half of Republicans, compared with only about one-third of Democrats, represent districts with an unusually high concentration of people lacking health insurance.

The economically vulnerable districts that each side holds also present a stark demographic contrast. Low-income Democratic seats tend to be in urban centers with large nonwhite populations. In more than three-fourths of the Democratic seats with a median income below the national level, and in virtually all of the Democratic districts with more uninsured people than average, the minority share of the population is also higher than the national average.

Some low-income Republican districts also have large minority populations, particularly in Texas and Florida, where the GOP has made inroads into culturally conservative Latino communities. But mostly the low-income GOP seats are centered on working-class white areas, many of them outside metropolitan areas.

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In the 141 seats Republicans hold with more seniors than the national average, white residents exceed their national share of the population in 127 of them. Likewise, white residents surpass their share of the national population in more than four-fifths of the Republican-held districts that lag the median income. Nearly half of House Republicans represent districts in which all three things are true: They have more seniors than the national level, more white residents than the national level, and a lower median income than the national level.

All of this reflects how working-class white voters, many of them financially squeezed, have become the unquestioned foundation of the GOPs coalition at every level, from the House through presidential elections.

Biden is laying siege to those voters with a strategy of deemphasizing cultural disputes and stressing kitchen-table economic benefits. Democrats really are making appeals to these districts in a big way, Pierson said. Most of that infrastructure and climate [spending] is going to go on in red states. There really is a big effort to say, We are going to use policy to try to make our electoral coalition bigger.

A key element of Bidens courtship of these voters is defending the social safety net, especially Social Security and Medicare. The presidents repeated rejection of reductions in those programs, combined with former President Donald Trumps opposition to potential cuts, has resulted in the most obvious concession by House Republicans to their evolving electoral base: public declarations by Speaker Kevin McCarthy and other leaders that they will not target Social Security and Medicare in the cutbacks they are demanding for raising the federal debt limit this summer.

Republicans hope that exempting Social Security and Medicare will dampen any backlash to their deficit-reduction plans in economically vulnerable districts. But protecting those programs, as well as defense, from cutswhile also precluding tax increaseswill force the House Republicans to propose severe reductions in other domestic programs that many voters in blu-collar Republican districts rely on, potentially including Medicaid, the ACA, and food and housing assistance.

Will a Republican push for severe reductions in those programs provide Democrats with an opening in such places? Robert J. Blendon, a professor emeritus at the Harvard School of Public Health, is dubious. Although these areas have extensive needs, he told me, the residents voting Republican in them are generally skeptical of social-welfare spending apart from Social Security and Medicare. We are dealing with a set of values here, which has a distrust of government and a sense that anyone should have to work to get any sort of low-income benefit, Blendon said. The people voting Republican in those districts dont see it as important [that] government provides those benefits.

The one risk for Republicans in such areas, he noted, would be if voters conclude that they present a genuine threat to Social Security and Medicare. Even most conservative voters strongly favor those programs, Blendon told me, primarily because they view them as an earned benefit that workers have contributed to during their lifetime. If the GOP seriously pushes ideas such as converting Medicare into a voucher program, or diverting part of Social Security revenue into private investment accounts, then in districts with a lot of older people, they are going to get in trouble, Blendon said.

Pastor, the director of the Equity Research Institute, also believes that current Democratic arguments targeted at older and non-college-educated white voters that they are voting against their interests economically are unlikely to succeed. The problem, he says, is that those arguments dont directly address the way many voters also define their interests to include cultural and racial dynamics. Because Republican strength in these older, predominantly white, financially stressed districts is rooted largely in the alienation of white voters who fear the country is shifting on them demographically, Democrats must ultimately make a more explicit case to those voters about how all Americans can benefit from a more diverse and inclusive society, Pastor said. The Democratic Party needs to figure out how to talk more effectively about race and racismnot try to ignore it, but try to inoculate people against it, he said.

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Bryan Bennett, the senior director of polling and analytics at the Hub Project, notes that the majority of voters, including seniors, support Bidens approach to preserving the safety net for retirees: In a recent national survey, his group found that voters were nearly four times as likely to support stabilizing Medicare by raising taxes on the affluent rather than cutting benefits. There is quite a bit of economically populist appetite even among Republicans for raising taxes on the wealthy and corporations, Bennett told me. Even Medicaid, once seen as a program for the poor, now draws widespread support across party lines, he said.

Yet Bennett, too, is cautious about predicting that Republican efforts to cut the safety net will hurt them in districts that highly depend on it. The GOP, Bennett said, is gambling that it can cut programs that benefit the partys lower-income white base and still prevent those voters from defecting to Democrats by stressing other issues like immigration and the culture war.

If Republicans face any internal resistance to sharp cuts in the safety net, in fact, it may be more likely to come from their members who represent socially liberal white-collar districts that dont rely as much on these programs than from their members who represent the culturally conservative blue-collar districts that do depend on them. The Republicans who seem least concerned about targeting the social safety net are those who represent the places that need those programs the most. Thats another telling measure of just how fully the concrete has settled beneath a modern political alignment that revolves more around culture than class.