Active-duty military personnel can vote; join a political party or club; or donate to political organizations, as long as they do so as private citizens and not as representatives of the U.S. armed forces.
But they don't have carte blanche to engage in all political activities, and certainly aren't allowed to participate in seditious acts.
As investigators work to determine whether any active-duty troops took part in the attack on the U.S. Capitol last week -- and the Army investigates one of its own who organized a group to attend the Save America Rally beforehand -- questions have arisen as to what service members can and can't do politically and the consequences they face.
The extent of their involvement will likely determine whether they violated a Defense Department directive that spells out the limitations or broke the law under the Uniform Code of Military Justice, according to military law experts.
DoD Directive 1344.10 breaks down the rules when it comes to political activities -- policies that are oft-repeated by the services during election years to remind personnel of their rights and limitations, according to Rachel VanLandingham, a retired Air Force judge advocate general and law professor at Southwestern Law School in Los Angeles.
According to the directive, active-duty service members can vote and belong to a political party; give to political organizations and candidates; run for nonpartisan elected office; write letters to the editor in support of candidates or parties; place bumper stickers on their vehicles; and engage in voter registration drives -- as long as they do these activities as private citizens.
They cannot participate in partisan political fundraising activities, rallies or debates; manage campaigns; use their office or authority to influence or interfere with an election; solicit votes for a candidate or issue; serve as an officer in a partisan political club; speak at partisan gatherings; speak to the media as an advocate for or against a partisan political party or candidate; or engage in fundraising activities on federal installations.
Participation includes more than mere attendance as a spectator, according to the directive.
Army Capt. Emily Rainey, 30, is the first active-duty member identified as being under investigation for her participation in the rally.
The Associated Press reported Sunday that the psychological operations officer, with 4th Psychological Operations Group at Fort Bragg, North Carolina, organized a group of 100 members of Moore County Citizens for Freedom -- a self-described nonpartisan network "dedicated to the promotion of conservative values in Moore County through education and activism" to attend the D.C. rally to "stand against election fraud."
Rainey said she attended the Trump rally while on leave, didn't advertise that she was an Army officer and told her bosses ahead of time that she'd be going.
"I was a private citizen and doing everything right and within my rights," Rainey told The Associated Press.
She said she didn't know of anyone who entered the Capitol and that the group members were headed back to their buses hours before an emergency curfew took effect.
But even if Rainey didn't break any laws, her role as organizer of the bus trip could be problematic and she could be held accountable, military law experts said.
"If you're the organizer, you are exercising the leadership role. That does create a problem with the DoD directive," said Eugene Fidell, a former Coast Guard judge advocate general and military law expert who lectures at Yale Law School. "She organized a subgroup. I think that is problematic, right? That's basically a leadership role."
"It sounds like she was leading, and that's where the real problem is going to come in," she said. "You can attend a political event, but you're not supposed to be engaged in partisan political activities. I don't see how you can get more partisan, which is what she was doing."
Rainey was charged earlier this month with injury to personal property after she posted a video online of her removing caution tape from a playground closed during COVID-19 restrictions.
According to the Army, she received an "appropriate administrative action" and submitted her resignation in September. It is expected to go into effect in April.
More than 90 people have been arrested for the events at the Capitol, which briefly delayed certification of the Electoral College results and ended with vandalism, injuries and deaths.
Six people died during or after the assault, including a trespasser shot while allegedly trying to break into the suite of House Speaker Nancy Pelosi, and a Capitol Police officer who died of injuries sustained while trying to defend the building and those trapped inside. Three people died of medical emergencies, while another officer died of suspected suicide after the event.
At least 25 people are under investigation on domestic terrorism charges in the incident -- a group that may include active-duty or reserve troops, a defense official told USA Today.
The agitator who died, Ashli Babbit, served in the U.S. Air Force for 14 years. Retired Air Force Reserve Lt. Col. Larry Brock was arrested Sunday in Texas and charged with violent entry and disorderly conduct as well as entering a restricted building.
Illinois Democrat Sen. Tammy Duckworth, a retired Army National Guard officer, has called for an investigation into whether any military retirees or active members participated in seditious acts, worked to hinder the electoral count or stole property from the Capitol.
In a letter Monday to Acting Secretary of Defense Chris Miller, Duckworth said it would be a "disgraceful insult to the vast majority of service members" if anyone was found to have participated" and she urged him to "hold individuals accountable under the Uniform Code of Military Justice."
"Upholding good order and discipline demands that the U.S. Armed Forces root out extremists that infiltrate the military and threaten our national security," she wrote.
Brock's arrest has raised discussions on whether he could be tried in military court for a variety of seditious acts, but given that he is a retired member of the Reserve, he likely will be prosecuted in civilian court.
As for any active-duty persons found to have participated, it would be up to the military to determine whether they violated DoD policy, should be tried within the military court system or turned over to civilian courts.
Fidell said he favors charges against any military persons being handled by civilian criminal courts.
"There's an interest in having the country's civilian justice system defend the country, because the victim here is the country, not the military," he said. "This was an offense against the Republic, and I have no reason to believe right now that the normal machinery of federal law won't capture this misconduct."
VanLandingham disagrees. In the case of active-duty personnel, they should be tried under the UCMJ, she said.
"There needs to be a very strong deterrent message sent to their fellow military members that this kind of behavior absolutely will not be tolerated," VanLandingham said. "This is not what we do in the military, and you're going to face the consequences."
Several articles of the UCMJ could apply to any military personnel found to have participated in last week's violence, including Article 88, which prohibits commissioned officers from "using contemptuous words against the president, vice president, Congress, the secretary of defense and service secretaries" and other named officials; Article 133, conduct unbecoming of an officer; and Article 134, which forbids behavior that disrupts or neglects good order and discipline.
There's also Article 94, which states that anyone found guilty of attempted mutiny, mutiny, sedition or failure to report such efforts could be subject to the death penalty, dismissal from the military and/or life in prison.
In Rainey's case, or that of any other active-duty personnel found to be guilty of committing a crime or violating DoD policy, there is a "continuum of possibilities," VanLandingham said.
"She was either a spectator at a political event not in uniform, so not engaged in any misconduct; she crossed the line into impermissible partisan political activities by leading others to protest the certification of Electoral College votes; she violated military law by engaging in the very serious crime of sedition by intending to destroy the ability of Congress to do its job by helping create the riot scene on [Jan. 6]; or a lesser crime of conduct unbecoming an officer, depending on what exactly she did last week," VanLandingham said.
-- Patricia Kime can be reached at Patricia.Kime@Monster.com. Follow her on Twitter @patriciakime.