PORTLAND, Ore. – Mardy Widman has watched protests against racial injustice unfold in her hometown of Portland for more than seven weeks but stayed away because, at age 79, she feared contracting the coronavirus.

But that calculus changed for Widman when President Donald Trump sent federal law enforcement agents to the liberal city to quell violent demonstrations that he said were fueled by "anarchists and agitators." On Monday, a masked Widman was in the street with more than 1,000 other Portlanders facing down the agents — a far larger crowd than the city had seen in recent days, as it entered its eighth week of nightly protests.

"It's like a dictatorship," Widman, a grandmother of five, said of Trump. She held up a sign that read: "Grammy says: Please feds, leave Portland."

"I mean, that he can pick on our city mostly because of the way we vote and make an example of it for his base is very frightening," she said.

Far from tamping down the unrest, the presence of federal agents on the streets of Portland — and particularly allegations that they have whisked people away in unmarked cars without probable cause — has given new momentum and a renewed, laser-sharp focus to protests that had begun to devolve into smaller, chaotic crowds. The use of federal agents against the will of local officials has also set up the potential for a constitutional crisis — and one that could escalate as Trump says he plans to send federal agents to other cities.

Federal forces were deployed to Portland in early July, and tensions have grown since: first, on July 11, when a protester was hospitalized with critical injuries after a U.S. Marshals Service officer struck him in the head with a round of what's known as less-lethal ammunition. Then, anger flared again over the weekend after video surfaced of a federal agent hitting a U.S. Navy veteran repeatedly with a baton while another agent sprays him in the face with pepper spray.

Crowds had recently numbered fewer than 100 but swelled to more than 1,000 over the weekend — and they are once again attracting a broader base in a city that's increasingly unified and outraged.

U.S. agents again used force to scatter protesters Tuesday and deployed smoke bombs and rubber-coated bullets as some in the crowd banged on the doors of the U.S. Courthouse and attempted to pull plywood off the shuttered entryway.

"To the federal occupiers — you're not welcome here. You have done nothing but escalate tensions and harm our community members. We can handle our revolution ourselves. Go home," City Commissioner Chloe Eudaly said.

Larry Cosme, president of the Federal Law Enforcement Officers Association, said the federal agents were necessary because local forces have "refused to restore order to the city or cooperate with federal law enforcement attempting to protect federal property, personnel, and regain control."

"At the end of the day, we all have the same mission: to protect and defend the U.S. Constitution and the American people," he said in a statement. "State and local officials are failing at that mission."

But constitutional law experts said federal officers' actions in the progressive city are "unprecedented" and a "red flag" in what could become a test case of states' rights.

Elsewhere, the Department of Homeland Security said Monday it plans to deploy about 150 of its agents to Chicago to help local law enforcement deal with a spike in crime, according to an official with direct knowledge of the plans who spoke on condition of anonymity. The Trump administration also sent more than 100 federal law enforcement officers to Kansas City to help quell a rise in violence after the shooting death of a young boy there.

"We're going to have more federal law enforcement, that I can tell you," Trump said Monday. "In Portland, they've done a fantastic job."

For days after the death of George Floyd, protests against police brutality and racial injustice in Portland attracted thousands and were largely peaceful. But smaller groups of up to several hundred people have vandalized federal property and local law enforcement buildings, at times setting fires to police precincts and smashing windows. They have also clashed violently with local police.

A constant focus of protesters has been the federal courthouse, which sits in the heart of downtown and is now covered with graffiti and completely boarded up, with only thin slits cut into the plywood for federal agents to use as peepholes.

Portland police used tear gas on several occasions until a federal court order banned its officers from doing so without declaring a riot. Now, anger is building as federal officers deploy tear gas against demonstrators instead.