Here’s why Trump’s border wall won’t work

January 5, 2019 GMT

Donald Trump pledged during his presidential campaign to build a wall on the southern border of the U.S. that would stop “illegal” immigration from Mexico and Central America, and also block the entry of drugs. He told his supporters that Mexico would pay for the wall.

Now he states that the U.S., not Mexico, will pay for the wall. Trump is asking Congress for more than $5 billion to build part of it. But the wall in total will cost over $21.6 billion and take as long as three years to build.

But Trump’s wall won’t work. It won’t reduce the number of undocumented immigrants in the U.S. and could well have the opposite effect. Plus, it won’t stop drugs and contraband from entering the U.S.

Let me tell you why.

Almost one-quarter of the 44 million people living in the U.S. who were born in another country, or about 10.7 million people, are undocumented immigrants. These are the immigrants Trump wants deported. But he apparently doesn’t know that more than two-fifths of these undocumented immigrants, or almost 4.5 million, are visa overstayers. They entered the U.S. with legal passports and legal visas but either stayed past their visa expiration dates or otherwise violated the terms of their admission into the U.S., perhaps by accepting employment.


Most flew in legally from Asia, Europe and other continents, and entered at major airports in San Francisco, New York, Los Angeles, Houston and elsewhere. Trump’s wall won’t be high enough to keep them out.

There is no plan to address the issue of visa overstayers. The U.S. Department of Homeland Security does not match entry and exit records of people coming into and leaving the U.S.

Congress mandated an electronic entry-exit system more than 20 years ago, but it has not been implemented because of objections from the tourism industry and other groups. A biometric entry-exit system would keep tabs on most of the people entering and exiting the U.S. and would reduce the number of visa overstayers. But the implementation of such a system is not in Trump’s plans. He only wants a wall.

The 5 million to 6 million undocumented immigrants in the U.S. who are not visa overstayers are formally referred to by demographers and immigration officials as EWIs, persons who “entered without inspection.” They entered the U.S. without detection or used fraudulent documents when crossing the border. Almost all of them entered at the U.S.-Mexico border, and until recently most of them were from Mexico. Now, most are from Central America.

Demographers have conducted extensive research about EWIs. They are not criminals, and they don’t take jobs from U.S.-born Americans. Almost all EWIs end up doing work Americans don’t want to do. Demographers have found little, if any, evidence that EWIs harm or suppress the employment or wages of local people.


In his first address in 2017 to a joint session of Congress, Trump stated that EWIs cost the U.S. “billions of dollars a year.” But this is not true. About half of EWIs pay taxes. Millions of them file tax returns every year, paying for benefits they’re not permitted to use. In 2015, the IRS received more than 4 million tax returns from workers who don’t have Social Security numbers, and many of them are EWIs. They paid almost $24 billion in income taxes. And they won’t get any of it back in Social Security and Medicare payments.

What about the wall stopping violent criminals from entering the U.S? Trump stated in 2015 that his wall will keep criminals, drug dealers and rapists from entering the U.S. Extensive criminological research has shown time and time again that foreign-born people have considerably lower crime rates than do the U.S.-born.

Why won’t a border wall keep out EWIs? Only the strongest and most advantaged people attempt the crossing. Demographers have studied the “selectivity” of migration. They’ve shown that with Trump’s wall, the journey to the U.S. will become more dangerous, and many migrants will fail. But eventually most will succeed. Trump’s wall will not keep this strong-willed, motivated and talented population out of this country. Trump’s wall will cause the migrants to settle and stay in the U.S., and not return to their home countries.

Drugs? This is an easy argument to dismiss because most illicit drugs don’t enter the U.S. via people sneaking across the border. Researchers at the Brookings Institute have shown that most drugs smuggled into the U.S. do not arrive on the backs of those who cross illegally. The U.S. Drug Enforcement Administration reported in a 2015 assessment that Mexican drug cartels bring the bulk of their drugs over the southern border through ports of entry via trucks, passenger vehicles and tractor-trailers.

Trump states his wall will work because border walls have worked elsewhere. He has noted that China’s Great Wall is an example of the success of a physical barrier. No. China’s wall — actually a series of walls — took almost 2,000 years to build at a cost of hundreds of thousands of lives. But China’s walls did not keep out foreigners. The Mongols entered China despite the walls and ruled China in the Yuan Dynasty (1279-1368), and the Manchu entered China around the walls and ruled China in the Qing Dynasty (1644-1911). Indeed, virtually all the famous walls in the world did not/do not work.

I predict that if Trump’s wall is built, within 10 years there will be at least as many EWIs as now (6 to 7 million), maybe several million more. This means that along with the 5 million visa overstayers, there will be more than 11 million undocumented immigrants in the U.S., most of whom will become part of a permanently settled population of residents.

Thus, a $23 billion investment intended to wall people out of the United States will keep people in the United States. Trump’s wall simply won’t work.

Dudley L. Poston Jr. is a sociology and demography professor at Texas A&M University in College Station. He lives in San Antonio.