Nikki Haley, the governor of South Carolina, is the latest Republican to learn how important immigration has become to conservatives. In her response to the State of the Union address, she argued both that immigrants should be made to feel welcome and that we have to maintain control of our immigration policy. For these comments, she was denounced in some quarters as a moderate who had declared war on her own party's strongest supporters. Both the speech and the reaction offer more evidence that immigration control is becoming a more important, and defining, issue for conservatives.
Why the issue has become central is less clear. It's not because the problem of illegal immigration is growing; it has fallen in recent years. But that decline has coincided with at least seven factors that have raised the political importance of immigration for the right.
1. Low economic growth.
The economic expansion under George W. Bush was weak and ended in a brutal economic crisis, and the recovery afterward has been disappointing. For most people, incomes haven't been rising as fast as they did in the 1980s and 1990s -- and Americans who feel economically vulnerable are more likely to see immigrants as an economic threat.
2. Demographic changes among Republicans.
If Republicans are more concerned than they used to be about the wage pressure that immigration puts on the low end of the labor market, it's partly because more Republicans work there than in the past. The party has become more dependent over time on white voters without college degrees. These Americans, who are more exposed to competition from immigrants than white voters with more schooling, have seen their economic prospects stagnate or decline.
3. The growth of the immigrant population.
The immigrant population, and its share of the total population, has increased over time, and pockets of immigration have formed around more and more of the country. With more immigrants in more places, more native-born Americans have found themselves in competition with immigrants. At the same time, more Americans have grown unsettled by the social changes that accompany large-scale immigration. (Europe's difficulties in assimilating Muslim immigrants have probably also played a role in forming American conservatives' views.)
4. The unresponsiveness of elites.
Only a quarter of Americans favor increased immigration levels, but leaders in both parties have represented this group more than they have the people who want less immigration. In 2013, Jeff Sessions, a Republican senator from Alabama, offered an amendment to cap immigration at 33 million over the next decade. Nobody else voted for it. Republicans who want less immigration and more enforcement of immigration laws have come to feel that politicians aren't really listening to them on this issue. They aren't a tiny group of voters, and they resent their relegation to a fringe.
5. Partisan politics.
Immigrants have been voting increasingly for Democrats. Some Republicans think that they should respond by making it clear that they welcome immigrants. Other Republicans, though, have reacted to the same trend by wondering why national policy should keep bringing in more people who support the opposition on most issues.
6. The progress of arguments among conservatives.
Conservative thinkers, writers, and talkers have been debating immigration among themselves for two decades, sometimes bitterly. Respected conservative voices have been on both sides: National Review has argued for restricting immigration, while the editors of the Wall Street Journal have sometimes urged a constitutional amendment enshrining open borders. Over time, conservatives seem to have found the restrictionist arguments more persuasive. Among conservative publications, for example, the Weekly Standard switched sides, moving from open borders toward restriction. The economic argument for more immigration, for example, has fallen flat among conservative opinion-makers as the evidence has come in. In 2013, the Congressional Budget Office estimated the economic effects of legislation to give illegal immigrants a path to citizenship and increase legal immigration. It found that in 20 years, per-capita GDP would be 0.2 percent higher thanks to the bill.
7. Cascading effects.
As more and more influential conservatives made the argument for immigration control; as more and more Republican voters found their take- home pay falling behind their cost of living; as immigrants became more and more identified with the Democratic Party: Conservative Republicans found that more and more of the people they generally agreed with on politics and looked to for information about issues were skeptical about a path to citizenship for illegal immigrants and about increased immigration. Those voters who began with no strong opinions on the issue started leaning that way, and those who already leaned that way strengthened their views.
As I've said, none of this means that conservatism is now anti-immigration. But it does mean that conservatives are more skeptical of the benefits of large-scale immigration. They are more eager to see the immigration laws enforced. And they are more inclined to view someone who pushes against this mood-which is all Governor Haley really did--as unconservative. And the constellation of causes nudging conservatives toward a restrictive approach to immigration means, I think, that the shift is likely to continue.