(CNN) As President Donald Trump's trip to Arizona is certain to demonstrate, immigration remains one of the most polarizing issues in American politics. But the central political fault line around the dispute follows a surprising path.
The paradox of this emotional debate is that generally the states and communities with the fewest immigrants are pushing to reduce immigration over the objections of the places with the most immigrants.
Even as Republicans from President Trump to leading legislators in the House and Senate are driving to reduce both undocumented and legal immigration, the core of the GOP's electoral strength in both presidential and Congressional contests are the places with the smallest share of immigrants, US Census data show.
Likewise, apart from Texas, the coalition of states threatening litigation next month to overturn President Obama's legal protections for children brought to the US illegally by their parents is composed entirely of states with only very small numbers of the so-called "dreamers."
Up and down the ballot, this disparity is partly explained by the Democratic advantages among minority voters, whether native-born or naturalized citizens born abroad. But the consistency of this contrast also suggests that suspicion about immigration among the native-born population is generally more intense in places with little exposure to immigrants than in communities where such exposure is more common.
In higher-immigration states, "Their economies and communities are fully integrated with immigrants -- across the skill spectrum. Therefore, they see and feel the benefits of immigration in ways that more culturally isolated states do not," says Ali Noorani, executive director of the National Immigration Forum and author of the recent book "There Goes The Neighborhood," which explores how communities are adapting to changing demography. "But even the more culturally isolated states are conflicted when you look closely. ... Most Americans know and love the José or Mohammed they know; but are afraid of the José or Mohammed they don't know."
This consistent pattern is one element of the wider geographic and demographic divide that now splits the parties. In many ways, as I've argued before, the two parties' coalitions are now separated primarily by contrasting attitudes toward the hurtling economic, cultural and demographic changes reconfiguring American life.
Democrats rely on what I have called a "coalition of transformation" that is largely comfortable with these changes, from increasing racial diversity and tolerance for diverse lifestyles to the transition toward a post-industrial economy. This coalition revolves around voters who are younger, more diverse, heavily urbanized, and among whites, both more secular and more tilted toward white-collar professions.
Republicans mobilize a competing "coalition of restoration" centered on voters who feel eclipsed, or even threatened, by these same changes. This coalition tends to be older, preponderantly white, religiously devout, strongest outside of major cities, and increasingly tilted toward blue-collar workers.
Exposure to immigrant populations has become a central piece of these contrasting experiences.
At every level of federal elections, Republicans now hold dominant advantages in states and communities with relatively fewer immigrants.
In the 2016 presidential election, Donald Trump carried 26 of the 30 states where the share of residents born abroad is the smallest, according to the five-year 2011-2015 estimates from the Census Bureau's American Community Survey. The only exceptions were three smaller New England states (Maine, New Hampshire and Vermont) and Minnesota.
Conversely, Hillary Clinton carried 16 of the 20 states with the highest percentage of residents born abroad. Here the only exceptions were Florida, Georgia, Texas, and Arizona.
Nationwide, according to the 2011-2015 estimates, residents born in the US comprise 87% of the population while foreign-born residents contribute 13%. But as my CNN colleague Ryan Struyk has calculated, native-born residents account for 91% of the population in the states that Trump won and only 81% of the population in the states Clinton carried.
The same patterns extend through Congress. In the Senate, Republicans hold 43 of the 60 Senate seats from the 30 states where immigrants represent the smallest share of the population. That's slightly less than three-fourths of the total. Democrats control 31 of the 40 Senate seats in the 20 states where immigrants represent the largest population share. That's just over three-fourths of the total.
The pattern is virtually identical in the House. Republicans hold almost three-fourths of the House districts where immigrants lag their share of the national population. Democrats hold just over three-fourths of the districts where immigrants exceed their share of the national population.
Viewed from the other angle, three-fifths of House Democrats represent districts where the immigrant population exceeds the national average; fully 85 percent of House Republicans represent districts where it lags the national average. Outside of Florida, Texas and California, virtually all House Republicans represent low-immigrant districts.
Rep. Carlos Curbelo, who holds a South Florida district with significant communities of not only Cuban-Americans but also immigrants from Central and South America, is one of the few Republicans who represent a seat with a large foreign-born population. He says one reason so many of his GOP colleagues are drawn toward restrictionist measures is that most represent areas where immigrants remain foreign in every sense of the word.
"There is no substitute for getting to know people and interacting with people and observing them forming a part of your community, whether it's at church, or working at a restaurant, or a park," Curbelo says. "And obviously that type of interaction just humanizes people who would otherwise either look foreign or seem foreign."
Even so, Curbelo says House Republican attitudes on immigration may not be a monolithic as they appear. He acknowledges that a House version of the legislation recently introduced by GOP Sens. Tom Cotton of Arkansas and David Perdue of Georgia to cut legal immigration in half "would probably be close" to attracting enough votes to pass. (Trump has endorsed that bill.) But, Curbelo says, when it comes to protecting the young undocumented immigrants covered under former President Obama's Deferred Action for Childhood Arrivals, or DACA program, "I am confident that a majority of House Republicans would vote to preserve the program as it is ... and many others would vote to give these young people a permanent solution."
For now, though, a coalition of 10 Republican-controlled states has threatened legal action if the Trump administration does not rescind the DACA program by September 5. That coalition is led by Ken Paxton, the Attorney General in Texas, which ranks second only to California in the number of DACA applications that have been granted as of March, according to Department of Homeland Security statistics. Texas, whose state GOP has turned sharply right on immigration issues since the days of George W. Bush and even Rick Perry, accounts for 15% of all approved DACA applications.
But the other nine states that have joined the suit -- all Southern or interior states that Trump carried in 2016 -- cumulatively account for only about another 5% of all accepted DACA applications.
By contrast, the coalition of 20 attorneys general who sent Trump a competing letter on July 21 urging him to preserve DACA represent states accounting for 52% of all accepted DACA applications. California comprises just over half of that (27%), with the remaining states led by New York (6%), Illinois (5%), and North Carolina (3%). Even without California included, the states that urged Trump to protect DACA account for more accepted applications than the states that are threatening legal action against it.
That imbalance partly reflects the larger pattern of Democratic strength in states with stronger immigrant traditions. But Republican attorneys general from several high-immigration states -- particularly Arizona, Nevada, Georgia and Florida -- are conspicuously absent from the Texas-led lawsuit against DACA. Similarly, the legislation to halve legal immigration has provoked immediate criticism from several Republican senators from high-immigration states, including Marco Rubio of Florida, John McCain and Jeff Flake of Arizona and Thom Tillis of North Carolina.
Republicans with big immigrant constituencies, though, remain the distinct minority in the party. Which is why the internal GOP debate over immigration may be decided by the Rust Belt states that tipped the 2016 election to Trump.
Michigan, Wisconsin, Pennsylvania, Ohio and Iowa all rank in the bottom half of states in the share of their population born abroad. But with virtually every Midwestern metropolitan area suffering an exodus of native-born adults in their prime working years, many communities across the Rust Belt in recent years have actively recruited immigrants to stabilize their population base and revitalize their economies.
As a result, Republicans from this politically pivotal region have shown less enthusiasm than their counterparts in the South, Plains and Mountain West for restricting immigration: no Rust Belt state, for instance, joined the Texas-led lawsuit against DACA. Some, like Republican Michigan Gov. Rick Snyder, have even established initiatives to attract and integrate immigrants. House Speaker Paul Ryan of Wisconsin has been a vocal early critic of the Senate proposal to slash legal immigration.
Whether the Rust Belt Republicans mostly join, or resist, the push for a hard line may determine how far the GOP forces dubious of both undocumented and legal immigration can advance their agenda.