Some opponents of open borders have argued that open borders make it very easy for terrorists and other ill-wishers of a country to enter it and wreak havoc. A few of them have argued that current immigration policies in the United States and Europe, though very far from true open borders, have already been responsible for a lot of terrorism.

Arguments on the immigration-terrorism nexus

Here are some samples of the arguments made by immigration restrictionists:

In addition to their factual content, the arguments sometimes evoke the alien invasion metaphor. Quotes from their arguments are at the bottom of the page.


There are several lines of counter-argument, some of which are provided below:

  • The problems of terrorism are greatly exaggerated: For instance, John Mueller has argued (here, here, and in his book Overblown) that terrorist threats are greatly exaggerated by politicians, pundits, and the media for various reasons, and that overreacting to such threats can be counter-productive and endanger safety in other ways.
  • Tourist visas are a lot easier to get anyway: People interested in carrying out terrorist attacks have a wide range of options available other than immigrating. In particular, they can obtain tourist visas, which are generally a lot easier to get. The US issues about 4 million B1/B2 (business/pleasure visit visas, which allow visit durations of a few months) compared to about 100,000 H1B visas every year. Moreover, since B1/B2 visas are often multiple entry visas, the actual number of tourist visitors to the US in a given year is in the tens of millions. David Friedman makes this point in the blog post Immigration and Terrorism.
  • The absence of legal migration channels is responsible for large scale illegal immigration, which diverts law enforcement resources to combating it: This includes large scale illegal immigration along the southern US-Mexico border. By allowing more legal migration flows, security agencies could focus on genuine terrorist threats rather than trying to keep out peaceful workers. Note that despite the large scale illegal immigration, there have been almost no instances of terrorists smuggling themselves across the southern border of the United States. All terrorist attacks in the US carried out by foreigners have been carried out by legal immigrants, tourists, or people on non-immigrant visas, including some who overstayed their visas. For more, see terrorism and illegal immigration in the United States. Nonetheless, an insecure border is responsible for other problems such as drug trafficking, and reducing the pressure to immigrate illegally can reduce the resources that need to be spent on border control.
  • There are cheaper and more sustainable methods to tackle the problem of terrorism: This fits in with the general principle of keyhole solutions. The methods may include (depending on your diagnosis of the problems of terrorism):
    • Better intelligence networks that could detect and foil terrorist plots more effectively. As pointed out above, security agencies could focus more on genuine terrorist threats if greater legal migration channels reduced the security threats associated with illegal immigration.
    • Intellectuals and thought leaders could counter radical ideologies in the realm of ideas and seek to win hearts and minds against such ideologies. Interestingly, the free movement of people between countries could lead to more effective spreading of these counter-ideologies to people in the countries that are large-scale sources of terrorists.
    • Those who believe that terrorism is influenced by the poor political and economic systems in certain countries could seek ways to improve those political and economic systems. Interestingly, freer movement of people can help in these regards, through its direct effect on world GDP and ending poverty, and its indirect effects on immigrant-sending countries.
    • Those who think that such problems are exacerbated by aggressive foreign policy could seek changes to such policy.

    The upshot is that whatever your diagnosis of the causes of terrorism, there are probably ways of tackling these causes that more directly address the global problem than immigration restrictions.

  • If all else fails, there may be a case for maintaining current immigration restrictions on people from ethnic/religious backgrounds that are highly correlated with terrorism: For instance, for those who believe that Islamic immigration to the United States poses a unique threat, this may be a reason to maintain present restrictions on immigration from Islamic countries and self-identified Muslims from other countries. But it’s not a reason to restrict immigration of individuals from other countries. True, any immigrant from any country could succumb to the lure of radical Islam, but so could native born Americans, like John Walker Lindh and Adam Gadahn.

Here are some writings on these matters:

Terrorism and illegal immigration

Restrictionists often like to harp on the connection between terrorism and illegal immigration. However, the terrorism problem, to the extent it exists, is mostly a problem of vetting legal immigrants and people on tourist visas, and, at least in the US, has almost nothing to do with illegal immigration. For more, see terrorism and illegal immigration in the United States.

Quotes from restrictionist arguments

In the Front Page Magazine article, Hawkins and Anderson write:

The terrorist attacks of September 11, 2001, which killed 3,000 Americans, have brought the question of border security to the forefront of the nation’s agenda. Even among Hispanics, a U.S. subgroup thought to favor liberal immigration policies, a majority of 56% wanted “tougher immigration [controls] in light of security concerns,” according to a national poll commissioned by a Hispanic business magazine in late 2003.[2]

All the terrorists who flew the hijacked airliners into the World Trade Center and the Pentagon had come into the United States from the other side of the world with the intent of carrying out their premeditated plot. America’s natural barriers – the great oceans which traditionally have protected America from foreign attacks – failed to provide security in this case because the enemy did use ballistic missiles or a naval armada. The traditional safety afforded to the United States by the vast oceans separating the country from foreign powers and foreign strife was not breached by ballistic missiles or an invading armada. Our enemies used normal commercial methods of transportation and exploited America’s laxity about possible threats from strangers in its midst. The terrorists’ visa applications had been rubber-stamped by U.S. consular officials despite flagrant errors and suspicious answers to security-inspired questions.[3] On arrival, the terrorists simply blended in the general population – which already accommodates more than 8 million illegal immigrants — and went about their business of planning mass murder. Half of the 19 hijackers made their deadly 9/11 airline reservations on an Internet travel site.

Since the first World Trade Center bombing by Arab-Muslim fanatics in 1993, forty-eight foreign-born Islamic radicals have been charged, convicted, pled guilty or admitted involvement in terrorism within the United States since 1993. According to a report by the Center for Immigration Studies, 16 of the 48 terrorists were on temporary visas (primarily tourists); 17 were legal permanent residents or naturalized U.S. citizens; 12 were illegal aliens; and 3 had applications for asylum pending (including Ramzi Yousef, the Iraqi mastermind of the 1993 World Trade Center Attack).[4] In addition to the dozen who had entered the country illegally, ten of those who had entered by legal means had subsequently violated the terms of their admission by overstaying their visas. All the 9/11 hijackers entered the U.S. on temporary visas, except Ali Mohammed, a leading member of al Qaeda, who was a naturalized U.S. citizen.

The United States has at sea the largest navy in the world and is developing a national missile defense system to frustrate overt military attacks on the country. But the day-to-day security of its borders is a broken system that has been unable to stop small groups of terrorists, let alone a mass migration that outnumbers the largest armies of history. It is estimated that 700,000 illegal immigrants simply walked across the U.S.-Mexican border last year and moved inland without interception by the thinly deployed Border Patrol.[5] The demographic shifts caused by unregulated mass immigration can have adverse impacts on national stability that rival or surpass the effects of war.

Despite these widely known and universally accepted facts, every major reform of the immigration laws over the last forty years has served to systematically undermine existing protections and controls, to open America’s borders wider and to call forth a larger flow of legal and illegal migration.[6]

In a similar vein, in the VDARE.com article, Peter Brimelow writes:

Yet, to paraphrase the famous slogan of the 1992 Clinton election campaign, “it’s the immigration, stupid.” It is immigration policy that has imported foreign ethnic conflicts, created impenetrable ethnic enclaves and mafias, diluted vetting procedures to the point where mass murderers can learn their skills here on student visas, overwhelmed the law enforcement agencies and – we will almost certainly learn – reduced the citizenship oath to a sick joke.

As with the immigration restriction of the 1920s, it may be immigrant terror attacks that finally frighten the cheap-labor business lobby into patriotism.

"The Efficient, Egalitarian, Libertarian, Utilitarian Way to Double World GDP" — Bryan Caplan