The recent images out of Portland — camouflaged federal agents pulling people into unmarked vans, firing off tear gas and flash grenades, and beating protesters with batons — have shocked the nation. Many people would like to believe that such violence by agents of the state are what one might witness in Pinochet’s Chile, but the truth is that the scenes from Portland are all too American.

Many of the agents in Portland are members of Border Patrol Tactical Unit (BORTAC), a part of U.S. Customs and Border Protection. Since 9/11, CBP has ballooned to more than 60,000 personnel, making it the largest law enforcement agency in the federal government. In recent years, BORTAC units have even been sent to Iraq and Afghanistan as part of Operation Iraqi Freedom and Operation Enduring Freedom.

What’s happening in Oregon reflects the long history of unprecedented police powers granted to federal border agents over what has become a far more expansive border zone than most Americans realize. The Trump administration’s deployment of BORTAC units to suppress protesters in Portland should compel Congress to rein in the power of these militarized forces, which we have tolerated for far too long.

The original Border Patrol, the precursor of the CBP, was established in the 1920s. For many of its early years, it operated as a law unto itself, known for racial profiling and brutality. From the beginning, its agents fell prey to mission creep. Rather than confining themselves to the national boundaries in policing immigration and smuggling, they often pushed their patrols to strategic points many miles into the interior.

After World War II, Congress codified the broad powers that the agency had assumed for itself. It passed a law in 1946 giving Border Patrol agents authority to arrest undocumented immigrants and to search vehicles “within a reasonable distance from any external boundary of the United States,” without the warrants that would usually be required by the 4th Amendment to protect against unreasonable search and seizure.

In 1953, the Justice Department unilaterally decided that this “reasonable distance” extended 100 miles into the interior from the international land borders with Mexico and Canada, as well as from the U.S.’ maritime borders. The repercussions of this decision have turned out to be profound.