America’s gun culture has been a subject of intense interest and controversy for years, with concerns frequently raised about shadowy militias, paramilitary extremists, and unstable zealots in possession of alarming quantities of explosives and firearms.

Amid the current din over assault weapons and body armor, consider one domestic organization’s fearsome arsenal of military-style equipment.

In the space of eight years, the group amassed a stockpile of pistols, shotguns, and semiautomatic rifles, along with ample supplies of ammunition, liquid explosives, gun scopes, and suppressors. In its cache as well are night-vision goggles, gas cannons, plus armored vests, drones, and surveillance equipment. Between 2006 and 2014, this organization spent nearly $4.8 million to arm itself. Yet its aggressive weapons buildup has drawn almost no public attention.

Does all this firepower belong to a jihadist terror cell? A right-wing hate group? A vicious urban gang?

None of the above. It is the Animal and Plant Health Inspection Service, an agency of the US Department of Agriculture, that has built up such a formidable collection of munitions. And far from being an outlier, it is one of dozens of federal agencies that spends lavishly on guns, ammunition, and military-style equipment.

A report issued this month by American Transparency, a nonpartisan watchdog that compiles data on public expenditures, chronicles the explosive — and expensive — trend toward militarizing federal agencies, most of which have no military responsibilities. Between 2006 and 2014, the report shows, 67 federal bureaus, departments, offices, and services spent at least $1.48 billion on ammunition and materiel one might expect to find in the hands of SWAT teams, Special Forces soldiers — or terrorists.

The largest share of that spending has gone to traditional law enforcement agencies, such as the Department of Homeland Security, the FBI, and the US Secret Service. But the arms race has metastasized to federal agencies with strictly regulatory or administrative functions. The Internal Revenue Service, for example, now spends more than $1 million annually on firearms, ammunition, and military gear, double what it was spending a decade ago. Since 2006, the Department of Veterans Affairs — which has been sharply criticized for episodes of fatal incompetence in patient care — has poured nearly $11.7 million into guns and ammo. Even the Smithsonian Institution and the Social Security Administration have each devoted hundreds of thousands of dollars to weaponry.

Incredibly, there are now fewer US Marines than there are officers at federal administrative agencies with the authority to carry weapons and make arrests. The soaring growth of this federal arsenal alarms Adam Andrzejewski, the head of American Transparency’s OpenTheBooks.com, which researched and assembled the new report. “Just who,” he asks, “are the feds planning to battle?”

Arguments long and loud about all the deadly firepower in the hands of private US citizens regularly engage liberals and conservatives. Far less notice has been paid to all the deadly firepower in the hands of federal bureaucrats. “The government itself has become a gun show that never adjourns,” remarks former US senator Tom Coburn. Dozens of federal agencies — entities that will never be called on to fight foreign enemies — now pack heat at unprecedented levels. Perhaps that, too, is something Americans should be arguing about.

Jeff Jacoby is a columnist for The Boston Globe.