Published 8:21 PM EDT Oct 18, 2018
In a series of tweets fired off Thursday morning, President Donald Trump delivered his most extreme threat yet to the governments of Mexico and Central America: “If they don’t stop a caravan of Hondurans trying to reach the U.S. to apply for asylum, he vowed to use the U.S. military to "CLOSE THE SOUTHERN BORDER!"
It’s unclear whether Trump is seriously considering a complete closure of the 2,000-mile border with Mexico, or if he’s using the threat simply to get America’s southern neighbors to cooperate, or that he’s just trying to rally his political base less than three weeks before the midterm elections.
But if sealing the border is realistically on the table, then that raises countless questions over the authority of the president to do so, the logistics of such an endeavor, and the widespread consequences it would have on Americans’ ability to trade, travel and even eat.
"A shutdown of the border, even for a temporary period of time, would have dramatic and devastating economic consequences," said Peter Boogaard, a former Homeland Security official in the Obama administration now working for FWD.us, an immigration advocacy group.
The first question, whether Trump can close the border, is a simple one to answer: yes.
"You can certainly stop entries coming across the border, whether its truck traffic or cars or pedestrians," said Gil Kerlikowske, former commissioner of U.S. Customs and Border Protection. "Logistically, that's possible. The gates are closed, and you say, 'Right now we're not taking entry.'"
Previous examples are rare. President George W. Bush partially closed the southern border following the 9-11 terrorist attacks, requiring full inspections of every incoming pedestrian and vehicle that led to days-long waits. President Ronald Reagan temporarily closed ports of entry along the southern border in 1985 following the kidnapping and murder of a DEA agent in Mexico.
"(Reagan) wanted answers from Mexico and wasn't getting them, so he shut the border down," Thomas Homan, Trump’s former head of Immigration and Customs Enforcement, told Fox News on Thursday. “It wasn’t long before Mexico, unfortunately, found him, he’d been tortured and murdered, but they also arrested the people who committed that crime. It worked.”
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The situation gets more complicated if Trump is contemplating using active-duty members of the military to help seal off the massive sections between those ports of entry, a 2,000-mile stretch from Brownsville, Texas, to San Diego, Calif.
The National Guard can definitely be deployed inside the U.S. Several presidents have done so, mobilizing those to assist along the southern border, respond to natural disasters, and help in the war on drugs. Trump has already done the same, issuing an order in April that sent 2,100 National Guard troops to help stop what Trump describes as a “crisis” level of illegal immigration.
But it's less clear if a president can order active-duty members of the Army, Navy, Air Force and Marines to patrol the southern border.
The Posse Comitatus Act of 1878 bars active duty military troops from performing domestic law enforcement functions. Legal and military experts have long cited that law as a barrier to domestic deployments of the military.
"The Department of Defense really doesn’t like to use the military in this law enforcement role. It blurs the line," said Christine Wormuth, a former undersecretary at the Defense Department and now director of the International Security and Defense Policy Center at the Rand Corporation. "The United States public doesn’t want the military to be policemen."
But the federal government has created some carve-outs that have allowed for domestic deployments. In 1991, Congress passed a law that allows the Pentagon to assist federal and state law enforcement officials during domestic anti-drug operations. That led to a 1997 incident in Texas where a Marine on a drug-surveillance mission shot and killed an 18-year-old who was herding goats on his family's ranch. U.S. law also allows the military to respond to armed insurrections and the recovery of weapons of mass destruction.
The Trump administration has already been willing to push legal limits to crack down on immigration, as its done to implement its travel ban, punish so-called "sanctuary cities" and end programs that have protected more than 1 million immigrants from deportation. Put that all together and some military experts feel that Trump could find a way to deploy active-duty military to the border in the name of national security.
"He has to work with Congress, and there's some bureaucratic, legal procedures he has to work through, but he can," said Frank Mora, a former deputy assistant secretary for the Western Hemisphere at the Department of Defense in the Obama administration.
Mora made clear, however, that going through that process would be "ridiculous on so many levels." He said the idea of deploying active-duty military along the border would not only take away from more important missions, but would be a disproportional response to stop "women, children and young men" from attempting to carry out the legal practice of applying for asylum.
"There are two audiences for this: his (political) base, just three weeks before the election, and to intimidate our friends and allies into submitting and doing what the president wants," said Mora, now the director of the director of the Kimberly Green Latin American and Caribbean Center at Florida International University.
Pentagon spokesman Lt. Col. Jamie Davis said the National Guard continues its deployment along the southern border, but that the Department of Defense "has not been tasked to provide additional support" as of Thursday afternoon.
Further complicating any closing of the border is the damage it would cause economically, not only in the four border states but throughout the country.
The U.S. State Department estimates that $1.7 billion in goods and services, and hundreds of thousands of people, legally cross the border each day. The U.S. gets nearly half (44 percent) of its fresh fruits and vegetables from Mexico, according to the U.S. Department of Agriculture.
"There's a reason ports of entry exist," said Mark Krikorian, executive director of the Center for Immigration Studies, a group that advocates for lower levels of legal and illegal immigration.
That’s why Krikorian, who wants the migrant caravan stopped, says Trump cannot seriously be considering a full closure of the border. Krikorian believes Trump is either bluffing to get Mexico to stop the caravan for him, or simply using the threat to rile up the Republican base before the midterm elections.
"This really does exemplify how Trump articulates what a lot of ordinary people feel when they see," a caravan of migrants headed toward the U.S., he said. "That's part of his strength — he gives voices to the reaction that normal people have to news events."
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