Budget cuts will drastically curtail the military’s ability to work with countries in South America and Latin America to stem the flow of cocaine and other illegal drugs into the U.S., a general said.

Automatic, across-the-board spending reductions, known as sequestration, “would be catastrophic” and “essentially put me out of business,” Marine Corps Gen. John Kelly told lawmakers on Thursday.

Kelly, who oversees American military activities in South America and Latin America as head of U.S. Southern Command, was responding to a question from Sen. John McCain, R-Arizona, chairman of the Senate Armed Services Committee, during a hearing to discuss the Pentagon’s fiscal 2016 budget.

Deficit-reduction legislation agreed to by Congress and the White House in 2011 will slice $1 trillion from the Defense Department budget over a decade, with half coming from sequestration. The automatic cuts are set to return in 2016 with greater effect, unless Republicans and Democrats agree on another spending plan — an unlikely prospect given the split between defense hawks and fiscal hawks in the GOP.

Kelly, who testified alongside Navy Adm. William Gortney, the commander of both U.S. Northern Command and North American Aerospace Defense Command, said the reductions will drastically curtail the U.S. military’s effort to stem the flow of cocaine, heroin, methamphetamine and other illegal drugs originating from South America.

“I would no longer be able to partner, almost at all, with the nations that we work with every day,” he said.

Another round of spending cuts would mean fewer U.S. Coast Guard cutters available to intercept smugglers, Kelly said. That could lead to a staggering drop in the quantity of drugs seized, he said.

“We got 158 metric tons of cocaine last year, without violence, before it ever even made it to Central America,” he said. “I do that with very, very few ships. I know that if sequestration’s happened, I would be down to maybe one, maybe two, Coast Guard cutters. That means, of the 158 tons that I would expect to get this year, I’d probably, if I’m lucky, get 20 tons. All the rest would just come into the United States along this incredible efficient network.”

He later explained, “Once it gets ashore in Central America and moves up through Mexico, we’re taking almost nothing off the market.”

Kelly said troops in his command help detect and monitor smugglers, while their Coast Guard colleagues actually interdict them.

“The interdiction phase really takes ships or cutters or some vessel that you can fly a helicopter from,” he said. “More ships, more cutters, means [interdiction of] more cocaine … You’re never going to be able to stop it all. But what you’re trying to do is drive down availability and drive up price, and then less people will start toying around with drugs.”

The Coast Guard, which falls under the Homeland Security Department, has long played a key role in international counter-narcotics programs. The cutter Boutwell last fall returned to Naval Base San Diego with more than 28,000 pounds of pure, uncut cocaine with a street value of more than $500 million after a three-month counter-drug patrol in the Eastern Pacific, according to the service’s budget request.

The Coast Guard for the fiscal year beginning Oct. 1 is requesting some $540 million for its surface assets, including funding for the fifth through the eighth new high-endurance National Security Cutters, as part of an overall budget of almost $10 billion, which is essentially flat from this year.

Meanwhile, the Pentagon requested an overall defense budget of $585 billion, including a $534 base budget and a $51 billion war budget. That’s an increase of about $25 billion, or 4 percent, in funding from this year.

Kelly said his command is encouraging military and law enforcement officials in Central America to work together in moving more vessels to border areas to better interdict smugglers. The government of Honduras recently intercepted multiple tons of cocaine, he said, in part “because we recommended changing how they go about their business.”

– Brendan McGarry can be reached at brendan.mcgarry@military.com