Though it received little coverage, Feb. 26 marked the 22nd anniversary of the 1993 World Trade Center attack. Since the attack happened at the hands of immigrants welcomed into the country by the federal government, it is worth remembering that the attack could have been prevented through careful enforcement of immigration laws and that the attackers were empowered by the 1986 amnesty.

Despite claims from amnesty advocates, there is little evidence that national security benefits from mass legalization programs aimed at rewarding foreigners who clandestinely enter the United States or overstay a visa. But there is evidence that such programs risk national security on account of the fact that the government does not seem to have the capacity to adequately vet applications.

{mosads}It is estimated that hundreds of thousands of illegal aliens were able to fraudulently obtain amnesty through 1986’s Immigration Reform and Control Act (IRCA), the comprehensive amnesty that was supposed to put an end to illegal immigration but was never really enforced with any gusto. The fraud was so significant that The New York Times called the amnesty “one of the most extensive immigration frauds ever perpetrated against the United States Government.”

One of the beneficiaries was illegal alien Mahmud Abouhalima, who overstayed a tourist visa and then falsely claimed to be an agricultural worker even though he worked as a cab driver. Issuing Abouhalima travel documents and a green card facilitated his terrorism, because he could then work at any job he wished and was able to travel to and from the United States freely. According to Time magazine, it was only after he received his green card in 1990 that he made several trips to the Middle East, where he received combat training. The legal status he acquired as a result of the 1986 amnesty is what made his training by al Qaeda possible. Had the U.S. enforced the nation’s immigration laws and returned him home, the attack might have been prevented.

If the former example shows why amnesty can facilitate terrorism, the case of Mohammed Salameh — who rented the truck used in the 1993 World Trade Center bombing — shows why an amnesty does not prevent terrorism. Salameh’s application for the 1986 amnesty was denied. But because the government did not deport failed amnesty applicants, he continued to live and work in the United States illegally and ultimately took part in the attack.

In sum, IRCA only helped terrorists and did nothing to hinder those involved in the 1993 attack.

Politicians promoting amnesties like 2013’s failed Senate bill or President Obama’s unilateral and unpopular Deferred Action for Childhood Arrivals (DACA) (and his planned, but currently blocked, expansion of the amnesty to illegal immigrant parents) have not made the case that the United States would be any better at vetting applications. The apparently clean records of some of the 1993 World Trade Center terrorists, prior to the attacks, would have made them natural beneficiaries of the Obama administration’s permissive immigration policies — on paper, they would look like “low priorities for deportation.”

Judicial Watch exposed the fact that the federal government could not even handle doing background checks for the few hundred thousand DACA applicants in 2012. The Obama administration decided to resort to “lean and light” background checks. Today, over 600,000 people have obtained DACA status and have received travel documents, Social Security accounts, work permits and other benefits. But Obama’s latest plan would expand the number of beneficiaries to 4 to 5 million people by changing the terms of DACA and extending similar benefits to illegal immigrants who have children in the United States.

Why would anyone think the government has the capacity to vet these applications? Furthermore, if the White House isn’t prepared to deport those whose applications are actually denied, how does this benefit national security? There is no evidence that anyone has been returned home after having their DACA application denied.

It is important to remember that background checks will likely not uncover crimes committed in other countries. And even if the administration did have access to the criminal databases of foreign countries (it doesn’t), some acts considered illegal under U.S. law may not be illegal in an applicant’s homeland.

On top of this, many working illegal aliens engage in a range of crimes from Social Security fraud to ID theft, but because the federal government rarely prosecutes illegal aliens for these crimes, DACA applicants can honestly claim a clean record.

Without a doubt, the overwhelming majority of people who are benefitting from Obama’s unilateral suspension of immigration law are not terrorists or violent criminals. But it only takes a few people to create significant loss of life and damage. If past amnesty programs are any guide, it is very likely that some problematic individuals will be empowered by President Obama’s immigration policies.

Feere is the legal policy analyst at the Center for Immigration Studies.