American conservatives have always been of two minds about immigration. The first instinct extols the virtues and benefits of immigration — a process that makes America wealthier and more culturally prosperous, as well as being consistent with our old historical roots. The second is concerned that immigrants make America less American — less prosperous, less free, and less culturally familiar.

In line with the second instinct, Republicans are typically more opposed to immigration than Democrats are, but this is a recent phenomenon. In the 1980s, Republican President Ronald Reagan supported amnesty for unlawful immigrants and went further, famously stating in his farewell address that America was a city on a hill, “and if there had to be city walls, the walls had doors and the doors were open to anyone with the will and heart to get here.”

In the 1960s, it was the Democrats and their labour union allies who killed the last large scale guest worker visa program, to protect organized labour. In the early 20th century, labourunions, eugenicists and their left-wing supporters pushed for virtually ending immigration while the free-marketeers of the day wanted to keep the doors wide open. Beginning in the 1990s, something began to change in the conservative movement.

Anti-immigration organizations such as the Federation for American Immigration Reform (FAIR), the Center for Immigration Studies (CIS), and NumbersUSA infiltrated the conservative movement and convinced many that opposing immigration was the conservative American position.

Even odder, FAIR, CIS, and NumbersUSA were founded, funded, and mostly staffed by pro-population control environmentalists. They opposed immigration on the grounds it damages the natural environment to pull immigrants out of poverty and thus increase their environmental impact. Mario Lopez’s exposé, “Hijacking Immigration?” in the Human Life Review reveals how pro-population control environmentalists “whose work is ultimately diametrically opposed to the right to life”, a right so important to the conservative movement, gained so much influence.

Many conservatives resisted the anti-immigration campaign. Many, like Representatives Paul Ryan (R‑WI), Raul Labrador (R‑ID), and Senator Marco Rubio (R‑FL), support increasing legal immigration and legalising some current unauthorized immigrants. With those and other exceptions, conservatives are generally more skeptical of the benefits of immigration and frequently voice their concerns.

One concern is that immigrants will use and abuse the welfare state — hurting American taxpayers. Immigration critic Senator Jeff Sessions (R‑AL) said this April, “once granted green cards and ultimately citizenship, illegal immigrants will be able to access all public benefit programs at a great cost to taxpayers.” Concern about immigrant use of benefits is rational, but it is easier to alter welfare policy than centrally plan the population in the hope of decreasing welfare dependency.

The welfare state is not an immutable characteristic of modern nation-states. Welfare benefits granted by the government can be withdrawn or altered by the government, especially to non-citizens. The United States limited welfare access to immigrants in its 1996 Welfare Reform law. Unlawful immigrants can never access public benefits and legal non-citizens cannot access public benefits for their first five years of residency. The only exception is emergency medical care in hospitals. Since 1996, some of the bill’s welfare restrictions have been repealed but most still stand.

Still, immigrants in the U.S. underuse welfare compared to similarly poor native born Americans. Immigrants are less likely to consume cash assistance, food-stamps, and Medicaid than poor Americans. When they do receive benefits, they are often for a lower cash value than the U.S.-born receive. If the U.S.-born poor used Medicaid as little as poor immigrants do, that pricey welfare program would cost 42% less.

Paradoxically, immigration might be the only way to sustain the welfare state just a little longer. The Journal of Health Affairs found that immigrants paid $13.8 billion more into Medicare Part A than they received in benefits in 2009. By contrast, U.S.-born Americans withdrew $30.9 billion more from the system than they contributed. If this rate continues as expected, Medicare Part A will be bankrupt in 2024.

Increasing legal immigration will not save America’s bankrupt entitlement programs, but it can give policy makers a few more years of financial breathing space to reform them. Related to welfare is a concern about immigration’s impact on the budget deficit. Most immigrants are poorer and less skilled than most Americans, so many assume they will be a burden on the public purse. In May of this year, the conservative Heritage Foundation produced a report arguing that immigration reform would cost the U.S. taxpayers $6.3 trillion over 50 years.

That report was criticized by scholars at virtually every other libertarian, free-market, and conservative think-tank in Washington D.C. for, among other things, assuming that the economy would not change in response to increased lawful immigration. In essence, that report violated a central precept of American free-market thought: Thou shall not use a static economic model to predict changes in dynamic economy. Due to immigrant productivity and the spill-over effects of having more workers, consumers, and entrepreneurs complementary to current Americans, the economy is likely to grow faster as a result of immigration reform, thus boosting tax revenue over time.

Conservative skepticism of immigration reform is vaguely related to reasonable concerns about fiscal and economic effects, but the actual impact of immigration is very different from how it is portrayed. The United States had a virtually open-borders immigration policy from the Founding until 1880, then shifted gradually toward closed orders by 1930. Centuries of mass-immigration has produced one of the most ethnically, racially, and religiously diverse societies in the world. The sooner American conservatives shed the influence of anti-immigration groups wielding faux-conservative arguments, the sooner they’ll realize that immigration is a traditional source of prosperity.