OPINION | Trump's militarized forces in Portland have no place in the U.S.

Video alarm of federal agents operating in Portland 2:52

Editor's Note: Benjamin Haas is a defense attorney for Human Rights First, an international non-profit, nonpartisan human rights organization that challenges the United States to fulfill its ideals. He served as an intelligence officer in the Army and was deployed to Afghanistan twice. The opinions expressed in this comment belong to the author. See more opinions on CNNe.com/opinion. 

(CNN) - The Trump administration's militarized response to the Portland protests and its war rhetoric, along with the President's threats to deploy the federal police in other major cities, represent a serious threat to both the American people and our democracy. 

Shocking videos show Department of Homeland Security (DHS) law enforcement officers pulling protesters off the streets of Portland and stuffing them into unmarked vehicles before they leave. The officers, dressed in the same camouflage pattern that I used as an Army intelligence officer in Afghanistan, are not easily identifiable by name or by their agency. The US Customs and Border Protection Service, a DHS agency, admitted to being involved in the arrest of protesters and released a statement to CNN saying: "Violent anarchists have organized events in Portland for the past few weeks with the deliberate intention to damage and destroy federal property, as well as injure federal officials and agents. These criminal actions will not be tolerated. " 

• READ: The protests in Portland, Oregon complete almost two months. So they started

Last week, the U.S. Attorney for the District of Oregon requested an investigation into the federal response, and DHS and Justice Department inspectors general began investigations into allegations that federal law enforcement personnel acted inappropriately. . 

But Chad Wolf, acting DHS secretary, has called the protesters "violent extremists" and has repeatedly branded them as dangerous criminals, while the president retweeted a publication comparing the protesters to an "internal terrorist paramilitary group." Meanwhile, teams of tactical border officers similar to those deployed to Portland have been dispatched to Seattle. 

Blurring the line between the army and the police is a risky proposition; Portland offers a surprising insight into the results. DHS officers in Portland remind me more of the special operators and infantrymen of the 10th Mountain Division I supported in Afghanistan than the police officers I hope to see serving and protecting American communities. 

Except that there is no war in the United States, and the institutions that must enforce the law must not be trained and equipped to act as if they were in one. However, the Trump administration would have us believe that protesters are enemies that must be defeated in combat. And in this context, DHS agents, acting at the behest of the Trump administration, have behaved unacceptably even in an armed conflict: they apprehend apparently peaceful protesters and beat others who pose no significant threat. Unsurprisingly, the militarized federal response and harsh tactics have escalated the situation in Portland, and Mayor Ted Wheeler received tear gas on Thursday when he joined a crowd of protesters. 

As if Portland's simple observations were not convincing enough, studies suggest that militarized law enforcement is not helpful to the police and harms community safety. A study in 2018, for example, found that "militarized police do not improve the security of officers or reduce local crime" and "can diminish the reputation of the police among the general public." Another study found a "statistically significant and positive relationship" between a Defense Department program channeling surplus military equipment to state and local law enforcement agencies and "gunshot deaths involving officers."

The Trump administration's highly militarized approach to law enforcement also presents potential dangers to the military. Public confidence in the Army is high, but confusion about his role or the false perception that he is involved in these federal responses to the protests could damage his relationship with society. This may be, in part, the reason why during a recent hearing on Capitol Hill about the military's involvement in responses to protests in June, Chairman of the Joint Chiefs of Staff, General Mark Milley, pointed out the importance of maintaining a "Visual distinction" between "what is military, and what is police". 

With all these drawbacks, perhaps it should come as no surprise that the United States has wanted to maintain a separation between the military and the police. There are limited exceptions, including the Insurrection Act, which Trump suggested he would use to deploy active-duty military personnel in response to the protests in June. 

After meeting stiff public opposition from retired military leaders and his own Defense Secretary Mark Esper, Trump turned away from this threat. But now, by deploying federal paramilitary law enforcement elements, the president has found a way to achieve the same effect: use the image of the military to intimidate and repress protesters. 

Trump appears to be trying to avoid the swift rejection he sparked among retired high-ranking military officers when he considered wielding active duty military troops in June. And in doing so, it is shattering the spirit of the American principle that separates the military from the police. This is more like the behavior of foreign authoritarians, not of American presidents. 

Portland has made clear the damaging effects of the militarization of law enforcement. Trump can feel tough deploying federal law enforcement officers as soldiers to terrorize Portland. But, as always, he seems motivated by his own desire to present himself as a strong man and to please his political base. Their actions do not serve the best interests of our democracy, the American people, the good police, or the military. Unfortunately, it seems that other cities in the country will only become additional cases in this regard.