ERIE, Pa. — With or without a huge wall along the southern border, states far from Mexico will continue to feel the effects of immigration — just not in the way most Americans might think.

That’s because immigration will change the demographics — and electoral power — of the states Donald Trump depended on to win the presidency.

Trump — who focused throughout the campaign on curbing illegal immigration — won after flipping an entire region from blue to red, from Wisconsin to Michigan and into Ohio and Pennsylvania. Paul Sracic, a political science professor at Youngstown (Ohio) State University, explains that Trump “could have lost Florida and still won, something the last Republican president, George W. Bush, never could have done.”

That outcome led Republicans to gleefully declare they had broken down the supposedly impregnable “blue wall” of electoral votes that was expected to guarantee Democratic presidential victories forever. As Sracic said, “All four of these states voted for Barack Obama twice.”

You might not expect illegal immigration to be a pressing concern in the states bordering the Great Lakes, about as far north of Mexico as you can get and still remain in the United States, Sracic points out: “The percentage of the population made up of illegal immigrants in each of these four states ranges from a low of 0.9 percent in Ohio to a high of 1.8 percent in Indiana.” Compare that to Nevada and Texas, where the numbers are 7.2 percent and 6.8 percent, respectively.

But that’s the problem. The 14th Amendment requires that, in apportioning congressional representatives based on population, we count the “whole number of persons in each state.” The Supreme Court affirmed that method of counting last year in Evenwell v. Abbott.

So illegal immigrants are essentially represented in Congress alongside legal citizens, because the Census counts both.

Since the Census is the determining factor in the number of House seats allocated to each state, those states with large numbers of illegal immigrants get extra seats (and more power to determine appropriations, electoral votes, etc.) at the expense of others.

States like Michigan, Ohio, Pennsylvania.

“Three of the four states that swung to Trump in the Upper Midwest lost seats in 2012, after the 2010 Census was taken,” Sracic said. Ohio lost two; Michigan and Pennsylvania, one each. “Meanwhile, Texas gained a whopping four seats, while Nevada gained one.”

Right now, Ohio is projected to lose another congressional seat following the 2020 Census.

To be fair, other factors (climate, jobs, taxes, etc.) contribute to population shifts. But Sracic cites an American University study that found, “If only citizens were counted when apportioning House seats, Michigan and Pennsylvania would each see their one seat restored and Ohio would get back one of the two seats it lost after 2010.”

Using that same methodology, California would lose five seats and Texas two seats.

Another way of saying all this is that three of the four Upper Midwest states that swung to Trump in 2016 would gain political power — electoral votes, too — if the number of illegal immigrants were reduced or not counted for census purposes in states such as Texas.

For years, rural and Rust Belt America have seen their numbers, power and influence in Washington wane. Pennsylvania had 36 House seats in 1933, twice the number it holds today; Nevada had only one at-large seat back then.

When most people discuss the impact of illegal immigration, they generally become agitated over security risks and job losses. They rarely consider how population shifts occurring hundreds of miles away can dramatically alter political bases, alliances and power among the states.

Candidate Trump turned illegal immigration into a winning issue in November and, as president, he hinted at expanding the issue by claiming that illegal voting unfairly tipped the popular vote against him.

If he or his supporters, in and out of politics, build on the issue by pointing to the impact on congressional representation, they could ignite entirely new passions in the states most hurt by it — the ones that helped him win, and that he hopes will help him keep, the White House.