ON SATURDAY, President Trump issued a memorandum authorizing a domestic deployment of the US armed forces. Although widely reported as an order to federalize National Guard troops to counter protests in California, the order is far broader, also authorizing the secretary of defense to use federal active-duty military forces.  

The order is not limited to California: it has no geographic restrictions and no expiration date. Since then, the president stated, “We’re gonna have troops everywhere,” and Defense Secretary Pete Hegseth mobilized the US Marines.  

As a civil rights lawyer at the American Civil Liberties Union and US military veteran, I know the president’s order is a significant abuse of power. It is an affront to the core principles of our democracy. And it is incumbent upon every American to call for this order to be rescinded immediately.  

The US military is a potent force for defense against external adversaries. The Defense Department commands more than one million uniformed personnel on active duty, and can potentially activate almost a million more from the Reserve and National Guard. Its units are equipped with the most powerful and sophisticated weapons, surveillance, and logistics technologies in the history of the world. They are backed by a budget of nearly $1 trillion per year and work within systems designed to promote and ensure efficiency and secrecy.   

But a force that exists for protection also has the potential to be a dangerous tool for internal repression. Authoritarian governments throughout history have blurred the lines between military power and civilian law enforcement. Once the door is open to military forces targeting some of the population, that door is very hard to close. When the rule of law becomes the rule of force, no one will be safe.   

Our nation’s founders understood these principles. The battles of Lexington and Concord were fought by the revolutionaries against a military occupation of their communities by their own sovereign. Military occupation was one of the founders’ listed grievances in the Declaration of Independence, an intolerable injustice perpetrated by the monarchy they rejected. The separation of military power from domestic law enforcement is a core American tradition.  

Deploying the tools of war inside our own country to suppress constitutionally protected expression and assembly is dangerous and un-American. Such actions would not only run counter to core constitutional principles but also offend the honorable service of the many uniformed Americans who still seek to protect rather than undermine our democratic values.   

Over time, lawmakers have created important legal restrictions to prevent presidents from deploying the military against civilians. One protection is the 1878 Posse Comitatus Act, which specifically forbids the use of the federal military as a domestic police force. There are certain exceptions to that prohibition — Congress permits deployment of uniformed troops on American soil in extreme emergencies. But there is no such emergency today.   

In California, ICE reportedly used aggressive military tactics to make arrests in restaurants and shopping centers, firing tear gas and other chemical agents against protesters, press, and bystanders present on the scene.  

Such actions can create a pretext for military deployment — and people have every reason to believe that Trump will use that deployment to intensify the aggressive tactics we saw in Los Angeles, in keeping with his administration’s broadly repressive agenda.  

For months now, Trump and his officials have been waging a campaign to twist the military into a heavily armed loyalist force. Since January 20, Trump has fired the only Black person and the only woman on the Joint Chiefs of Staff, as well as the head of the National Security Agency, without any apparent explanation.  

Trump and his officials also fired without justification top military lawyers tasked with advising military leaders on compliance with the law. Secretary of Defense Hegseth then directly commissioned his own personal lawyer as a commander in the Navy and reportedly assigned him to overhaul the training of military lawyers. These actions by the president and secretary of defense are so extreme and dangerous that, even as early as February, the former secretary of the Air Force publicly declared the country to be entering “uncharted territory.”    

That is only more true today.  

California has now filed a lawsuit to block the president’s order. But political abuses also require political action.  

Bravery from public officials and private citizens is key to rejecting the deployment of our military against the people of our own country. That means public officials and employees need to speak out against this order. It means that legislators must assert their power to protect the public. And it means that every concerned citizen must exercise our constitutional rights to assemble and be heard. We must demand that the president’s order be rescinded now, before it is too late.    

Dan McFadden is a managing attorney at the ACLU of Massachusetts. He served as a surface warfare officer in the US Navy from 2001 to 2006.