Armored trucks, military uniforms, and the glow of the U.S. Capitol — a tableau more fitting for wartime than domestic policing. Yet under orders from President Donald Trump, National Guard units have been dispatched to cities like Portland, Chicago, Los Angeles, and Washington, D.C., in a bid to quell protests and bolster immigration enforcement.
The move has reignited a debate as old as the republic itself — where does presidential power end when the military enters American streets?
At the heart of this question lies the Posse Comitatus Act of 1878, a statute born from a deep American distrust of using soldiers for civilian control. The law sharply restricts the use of federal military forces for domestic policing — a boundary meant to safeguard personal liberty. But like many American laws, its rigidity is softened by exceptions.
The National Guard occupies a gray zone. When commanded by a state’s governor, it operates outside the scope of Posse Comitatus — often aiding during floods, fires, or civil emergencies. Yet once “federalized” and placed under presidential command, that protection fades.
The Trump administration has leaned on Section 12406 of Title 10 of the U.S. Code, a provision allowing the president to summon state National Guards to “repel invasions” or “suppress rebellions.” It’s a legal needle to thread — technically compliant with the law, but politically fraught.
The tension has already reached the courts.
A federal judge in Oregon, Karin Immergut, recently halted Trump’s deployment of 200 Guard members to Portland, calling the administration’s justification “untethered to the facts.” The court found no credible rebellion, no invasion — only a stretch of presidential authority. The White House quickly appealed.
But in another case, the 9th U.S. Circuit Court of Appeals viewed things differently, backing Trump’s earlier deployment to Los Angeles. There, violent protests had disrupted federal operations, the court said — satisfying the law’s conditions.
Meanwhile, Illinois and Chicago have joined the legal fray, filing fresh suits to block new deployments.
If Trump loses in court, another, more explosive option remains: the Insurrection Act — a relic from 1807 that allows the president to deploy military forces inside U.S. borders during rebellion or breakdown of law and order. It has been used only 30 times in American history, most notably during the civil rights era to enforce desegregation orders and protect marches against racial violence.
Trump has signaled he might go there. “If courts keep blocking the National Guard,” he told reporters, “we’ll consider all legal tools available.”
Whether that’s a promise or a warning depends on which side of the barricade you’re standing on.
