A husband and wife have been charged with unlawful use of a weapon for pointing guns at demonstrators outside their home in St Louis, Missouri.
Lawyers Mark and Patricia McCloskey drew guns on racial justice protesters marching through the grounds of their $1.15m mansion last month.
The couple said they armed themselves because they felt threatened.
But St Louis' top prosecutor said their actions had risked creating violence at an otherwise peaceful protest.
"It is illegal to wave weapons in a threatening manner at those participating in non-violent protest, and while we are fortunate this situation did not escalate into deadly force, this type of conduct is unacceptable in St Louis," said Kim Gardner, who is the city's first black circuit attorney.
"We must protect the right to peacefully protest, and any attempt to chill it through intimidation will not be tolerated," she added.
The McCloskeys also face a charge of fourth-degree assault.
The couple's lawyer, Joel Schwartz, called the decision to press charges "disheartening as I unequivocally believe no crime was committed".
The couple, both personal injury attorneys who live on a private street, have said they were within their rights to defend their property.
Missouri Governor Mike Parson has said he was prepared to exercise his pardon powers if prosecutors brought criminal charges in the case.
"I don't think they're going to spend any time in jail," the Republican told a local radio station last week.
When he was a legislator, the governor co-wrote Missouri's "castle doctrine" law that justifies deadly force for those who are defending their homes from intruders.
On Friday, the couple made an appearance at a virtual Trump campaign event. Earlier, Mr Trump told the conservative news website Townhall: "They want to prosecute these people, it's a disgrace."
Video footage showed Mr McCloskey, 63, and his wife, 61, draw firearms as demonstrators marched past their mansion to the home of St Louis Mayor Lyda Krewson to call for her resignation on 28 June.
The mayor had infuriated activists by reading out on Facebook Live the names and addresses of people advocating defunding the police.
The McCloskeys' legal team has said two or three white protesters had threatened the couple and their property.
According to a police report on the incident, the couple said a large group of people had broken through an iron gate marked with "No Trespassing" and "Private Street" signs. One of the protest leaders maintained the gate was already open.
The march was part of a nationwide wave of demonstrations over police brutality and racism prompted by the killing of an unarmed black man, George Floyd, by a white policeman.
Ms Gardner is recommending that the husband and wife participate in a "diversion programme" designed to reduce unnecessary involvement with the courts.
It could see them ordered to take part in community service or a remedial course.
Class E felonies like unlawful use of a weapon can carry prison sentences of up to four years.