THE HISTORY OF IMMIGRATION to the United States is also the history of the response to immigration. Since the founding of the republic, intermittent surges of foreign-born newcomers have consistently produced hostility in parts of the population who feared economic competition and cultural subversion. In addition, with each wave some politicians exploited that fear by promising restrictions on immigrants to preserve the existing economic and social norms. That political manipulation has repeatedly cost the country the opportunity to engage in constructive debate on how best to design and implement sensible immigration policy. It’s happening again now.

An early illustration of the outburst of anger occurred in the 1850s after the Irish potato famine caused large numbers of unwelcome Catholics to enter an essentially Protestant country. Massachusetts voters led the response in 1854 when they elected members of the anti-immigrant Know Nothing Party to the governorship and to almost every seat in the Legislature.

The Know Nothings, formally called the American Party, started out as a secret society whose members were instructed to deny any knowledge of the anti-immigrant agenda. Once in power, they quickly passed laws to criminalize behavior they associated with Irish immigrants, such as beer drinking and gambling. They thought convents were suspect places and officially investigated them. Their main purpose was to preclude further Catholic immigrants and to withhold citizenship from those already here. Their platform said that “Americans must rule America, and to this end native-born citizens should be elected to all state, federal, and municipal offices . . . in preference to all others.” Most enduring was their 1855 amendment to the state constitution prohibiting spending tax money on schools sponsored by “any religious sect.”

Other state governments took similar steps. The large numbers of Irish new-comers during the mid-century wave were joined by substantial flows from Germany and elsewhere in northwestern Europe. Several years in the 1840s and 1850s saw more than 400,000 of those immigrants enter the United States. Their presence spread the Know Nothing response across many states.

A similar backlash later occurred in California after that state’s Chinese population surged dramatically in the wake of the gold rush and the construction of the transcontinental railroad. California adopted a new state constitution in 1879, which placed severe limitations on its Chinese population. The disdain for those immigrants was so strong that Congress followed up by passing the Chinese Exclusion Act in 1882, which essentially ended legal Chinese immigration to the United States. The restriction remained in effect until 1943. By that time China was our ally against Japan in World War II and a grudgingly grateful Congress authorized 105 Chinese immigrants per year to enter the country.

The next immigration surge peaked in the late nineteenth and early twentieth century when a wave of newcomers from southern and eastern Europe arrived at a rate that frequently exceeded a million per year. The cumulative impact brought the number of foreign-born residents in the US to a record level of almost 15 per cent of the total population. Urban areas on the east coast were particularly impacted. The census of 1900 found that 846,000 residents of Massachusetts, 30.2 per cent of the population, were foreign born.

In response, the anti-immigration movement forcefully reemerged and Massachusetts again contributed to the backlash against foreigners. A key leader was US Sen. Henry Cabot Lodge who worked his entire career to reduce immigration from anywhere other than northwestern Europe. He specifically sought to limit people from Italy, Russia, Poland, Hungary, and Greece. He saw them as a threat to the “English-speaking race” which had “mental and moral qualities” making them the most successful people in the world.

Lodge was a Harvard-educated scholar who articulated the anti-immigrant cause. In support of restrictive legislation on the Senate floor he said: “In careless strength, with generous hand, we have kept our gates wide open to all the world. If we do not close them, we should at least place sentinels beside them to challenge those who would pass through. The gates which admit men to the United States and to citizenship in the great republic should no longer be left unguarded.”

Lodge and his allies eventually prevailed and Congress passed a series of severe restrictions. In the post-World War I era, US immigration was reduced to historically low levels that persisted for more than a half century. The almost 15 percent of foreign-born people in the US in 1910 dropped to 4.7 per cent by 1970. Not surprisingly, anti-immigrant resentment dissipated during those decades.

The genesis for the current wave of immigration occurred in 1965 when Congress passed and President Lyndon Johnson signed the Hart-Celler Act repealing restrictive quotas. Supporters saw the law as consistent with civil rights and other anti-discrimination efforts made during the 1960s, but they did not believe it would significantly change actual immigration. Another Massachusetts senator, Ted Kennedy, was floor manager and expressed a common belief when he said the bill “would not upset the ethnic mix of our society.” In fact, the law had unexpected results, in part because it introduced chain migration.

The 1965 legislation opened the gates that Lodge and his allies had closed. In 1970 there were 9.6 million foreign born people in the United States. The numbers increased steadily over the next 20 years before accelerating during the 1990s. By 2000, the number was slightly over 31 million people and the pace continued until the onset of the Great Recession when the rate of growth subdued. The Census Bureau estimates the 2017 foreign-born number at 44.5 million people representing 13.7 per cent of the total.

A significant majority of foreign-born residents in the US are here legally. The number of unauthorized residents has dropped over the past decade and is now estimated at slightly under 11 million, less than a quarter of the foreign-born population. The Department of Homeland Security has reported that more than 80 percent of the unauthorized residents have lived here for longer than 10 years and that fewer than 6 percent of them entered the country during the past five years.

The slowing growth of immigration means that we have not matched the record-setting percentage of foreign-born established more than a century ago. But this wave has generated a response similar to those provoked by earlier waves. Even in a large and diverse country, the introduction of tens of millions of people over several decades can resurrect the recurring anxiety about competition, crime, and cultural erosion. There are ways for a thoughtful society to manage that anxiety but history shows that exploitive politicians use it to generate vote-producing fear.

President Trump’s focus on the southern border “crisis” is a mirage that appeals to voter anxiety, avoids solutions, and blurs the truth. There are real issues to deal with on that border but no one listening to Trump would know that more Asian than Hispanic immigrants have arrived in the US each year since 2010. His focus on the caravan “invasion” consisting of a few thousand asylum seekers from Central America has political utility but distorts reality. More than a million immigrants are admitted to the US every year through normal, non-asylum, processes. The number of asylum seekers is a small portion of the total. Last year, 22,491 people were granted asylum, the lowest number in decades.

Wall supporters, who obscure the difference between immigrants and asylum seekers, may not understand that even eliminating asylum altogether would have no real impact on immigration.

Trump is competent at symbol manipulation and continues to exploit the fear and anger arising from the recent immigration wave but he did not originate that response. Backlash has periodically recurred over two centuries and its impact is compounded when it is embraced by a political organization. The national Republican political calculus has found benefit in becoming the contemporary Know Nothing Party. They blocked a widely supported immigration reform bill in 2013 because it would effectively resolve an issue they wanted to use in elections. They doubled down in 2016 when the party’s national platform endorsed building a wall that “must cover the entirety of the southern border and must be sufficient to stop both vehicular and pedestrian traffic.” The wall was just part of a much larger anti-immigrant screed in which Republicans found it “indefensible to continue offering lawful permanent residence to more than one million foreign nationals each year.”

The successful political exploitation of anti-immigration fear precludes thoughtful debate and promotes polarization. US Sen. Lindsey Graham was both frank and correct when he said that the wall is “a metaphor for border security.” A country engaged in emotional discourse over a symbol will not undertake substantive solutions to a complex problem. Democrats, whose 2016 platform recognized a “broken immigration system,” intensely fight the wall without clearly advocating how to fix the larger system. The Trump wall will probably never have a tangible presence, but it already functions as an effective barrier to coherent policy debate.

The only resolution is comprehensive, extended, well-informed legislation that considers the economic and social risks and benefits of multiple types of immigration. We must thoughtfully answer multiple questions, including: what skills does the country need; what helps the economy; what might harm parts of the existing labor force; is chain migration appropriate; how is a refugee defined; is there a maximum annual number that should not be exceeded? We can hope that Washington decision-makers will someday be able to conduct a thoughtful debate to examine those questions and update our immigration laws. Coherent deliberation is the only way to defuse the recurring Know Nothing cycle that has for too long substituted for productive debate. Our current immigration framework is now more than 50 years old and needs to evolve thoughtfully.

Edward M. Murphy worked in state government from 1979-1995, serving as the commissioner of the Department of Youth Services, commissioner of the Department of Mental Health, and executive director of the Health and Educational Facilities Authority. He retired as CEO and chairman of one of the country’s largest providers of services to people with disabilities.