For many parts of the world, it is hard to predict which Donald Trump will enter the White House on January 20. Will it be the Donald Trump who promised to decimate ISIS in 100 days, or the Donald Trump who promised to avoid an Iraq-like quagmire? Will it be the Donald Trump who campaigned on building up a decrepit U.S. military, or the Donald Trump who said he would slash military spending to balance the budget? Will it be a Donald Trump who is eager to strong-arm China at the negotiating table, or the Donald Trump who promised to discard the Trans-Pacific trade deal designed to increase American leverage over the region?

While Trump continues to regularly contradict his own supposed views on U.S. foreign policy, his approach to the U.S. southern border is clear. He talked a lot about building a wall while running for president. Since winning, he’s repeatedly emphasized the seriousness of his promise.

“You think we are playing games,” Trump said earlier this month, at a rally in Wisconsin. “We’re going to build the wall, okay? Believe me. We’re going to build the wall. We have to. We have got to stop the drugs from coming in and the wall is going to be a big, big factor.”

In the Trumpist view, the lack of a continuous border wall between the U.S. and Mexico facilitates the flow of drugs, undermines U.S. wages, and provides a potential gateway for terrorists trying to find their way into the United States. The wall is a concrete way to address fears among Trump’s base surrounding immigration, an issue that gives concerns over jobs, wages, and terrorist attacks a common focal point along the southern border. This worldview is so compelling as a political vision that it has sometimes caused Trump’s national security team to back it up with fabrications. Michael Flynn, Trump’s choice for national security adviser, has wrongly claimed that there are Arabic letters written on the backs of signs along the Mexico border, intended to guide terrorists into the United States.

John Kelly, the retired Marine general who Trump has chosen to lead the Department of Homeland Security, has his own pattern of exaggerating the border threat. Between 2012 and his retirement in early 2016, Kelly served as head of U.S. Southern Command. In this role, he coordinated all U.S. forces in the Western Hemisphere south of Mexico, including the Caribbean and Guantánamo, which is home to the hemisphere’s largest overseas U.S. military base. As Obama trimmed the military’s budget with the sequester, and prioritized Asia and the Middle East over the relatively peaceful Western Hemisphere, Kelly complained that the budget cuts were undermining regional security.

In a 2014 interview, he said that the flow of drugs and instability in Latin America posed an “existential” threat to the United States. During a March 2015 hearing before the Senate Armed Service Committee, Sen. Mike Lee. R-Utah, asked him to explain why the southern border posed such a large threat. Kelly responded with these words:

…there’s 40,000 Americans that die every year from the drugs that move up through my part of the world, and into Bill’s [Adm. William Gortney, who was then head of Northern Command], and into our homeland ­­— 40,000 people a year. You know, since 9/11, there’s — half a million people have died from narco­terrorism, as we call it in — down where I live — narco­terrorism. Five hundred thousand Americans have died. Very few have died from, you know, traditional terrorism, if you will, since 9/11. It costs our country $200 billion a year to deal with the people that are into drugs but are not, you know, dying. So I see that as a huge, huge, huge threat.

Kelly’s first claim — drugs kill roughly 40,000 Americans each year — is accurate. It is also true that drugs have killed more than half a million Americans in the 15 years since 9/11.

But Kelly’s second claim to the Senate committee, that 500,000 Americans “have died from narcoterrorism” since 9/11, is a significant exaggeration. The real number of Americans who have died of post-9/11 terrorism in all its forms is well under 1,000, according to a 2014 study that was supported by the Department of Homeland Security. And at least one-third of the 40,000 killed by drugs annually do not die, as Kelly claimed, from drugs coming into the U.S. across the southern border, but from overdoses of legally prescribed opioids. Almost all of the profits from those addicts flow not to drug cartels but to pharmaceutical companies. Sales of legal opioids have quadrupled since 1999, particularly in those white, rural areas of the country where Trump’s support is strongest.

Kelly’s claim of 500,000 deaths doesn’t appear to be reflected in any known official numbers. The RAND Corporation, for example, estimated that less than 100 people in total died due to terrorism in the U.S. between 9/11 and 2009.

While it is true that drug-related violence poses an existential threat to Mexico and Central America, Kelly was wrong to suggest that is the case in the United States. The number of Americans killed each year in drug-related homicides is around 1,000, according to the Bureau of Justice Statistics. That is one thousand too many, but it does not add up to the half million post-9/11 U.S. victims of narcoterrorism that Kelly claimed had lost their lives in his testimony before the Senate committee.

“Prescription drugs make billions of dollars for Purdue and other pharmaceutical companies,” said Kathleen Frydl, historian and author of “The Drug Wars in America,” by email. “It may be preferable for John Kelly to pretend that narcotrafficking, rather than homegrown greed, lies at the heart of the opioid crisis.”

Kelly’s claim of 500,000 U.S. narcoterrorism deaths is more than a one-time slip of the tongue. He said the same thing later last year in a discussion at the Center for Strategic and International Studies:

…our country is right at 40,000 dead a year, year after year, from another kind of terrorism, narcoterrorism … the cocaine and the drugs and the network it travels on, it moves anything. Guns, women, other people, human beings. Uh, potentially terrorists. Potentially, anything. All you have to do is pay the fare. But the network is very, very well developed.

While the rhetorical link that Kelly makes between terrorism and immigration is central to Trump’s pitch for sealing the U.S. border, new walls are just one of many ways that Kelly will likely carry out his agenda at the Department of Homeland Security. DHS is a very young, very large, and very powerful federal agency created 11 days after the September 11, 2001, attacks. It is roughly one-tenth the size of the Pentagon in terms of budget ($52 billion vs. $524 billion) and personnel (240,000 vs. 2.3 million), and oversees almost all of the federal government’s operations relating to immigration. If confirmed by the Senate, Kelly will be responsible for a wide portfolio of security measures inside of U.S. borders, including responding to natural disasters, stockpiling vaccines, inspecting cargo, scanning luggage and passengers at airports, passing federal intelligence on to state and local police, and managing Secret Service protection for the president and his family.

Trump said he will triple the number of federal officers working to deport immigrants, and immediately deport 2 million to 3 million people now living on U.S. soil. He has called for the “extreme vetting” of Muslims trying to enter the U.S., and perhaps banning entirely those seeking entry from certain countries, such as Syria.

Kelly will be the first military officer to lead the agency, in a country with longstanding legal prohibitions against military involvement in domestic law enforcement. Kelly, like Flynn, another retired military officer, has frequently referred to the possibility that Middle Eastern terrorist networks could link up with human smugglers to move operatives or weapons of mass destruction across U.S. borders, a persistent fear in government circles. It has never been conclusively disproven as a possibility, nor has it ever demonstrably taken place. Adam Isacson, who covers security for the Washington Office on Latin America, said that Kelly perceives the region “in terms of complex networks of criminals looking to do ill within the United States.” The potential for cross-border terrorism threat should not be completely discounted, he added. “You only have to be right once,” he said.

The southern border narcoterrorism scenario was also graphically depicted in the 2012 film “Act of Valor,” produced with the help of the Navy and active-duty Navy SEALS. Real-life investigations into the drug-terror connection tend to turn up less spectacular results, as recent investigations by Pro Publica and The Intercept have shown.

Russell Baer, a spokesperson for the Drug Enforcement Administration, said there was no official tally kept of deaths caused by narcoterrorism. “There’s no specific way to answer that question,” he said, by email. “Narcoterrorism has more to do with using drug proceeds, or drug money laundering services, to support a terroristic cause throughout the world. We are all victims of narcoterrorism.”

Trump’s transition team did not respond to a request asking them to clarify or explain Kelly’s remarks.