The seditious conspiracy charges against the leader of the Oath Keepers militia and 10 others related to the January 6 Capitol attack have revealed an armed plot against American democracy that involved tactical planning and a formidable arsenal of weapons.

Court documents unsealed on Thursday provide the most detailed account to date of the level of planning by the far-right militia in the assault on the Capitol that was aimed at scuppering the certification of Joe Biden’s election win.

The documents describe the creation of rapid-response teams of armed militia members, the deployment of tactical gear and the stockpiling of weapons in a deliberate attempt to overturn the election of Democrat Joe Biden, who beat Donald Trump.

On January 6 thousands of pro-Trump rioters stormed the building injuring police officers and sending lawmakers fleeing. Five people died around the events, including a Capitol police officer and a Trump supporter shot by law enforcement. The attempt to stop Biden from becoming president failed.

The federal indictment alleges Stewart Rhodes, founder of the Oath Keepers, a far-right extremist group, conspired with 10 other members to oppose by force the lawful transfer of presidential power. The group stationed armed members on the outskirts of Washington to serve as so-called “quick reaction force” teams. Rhodes has pleaded not guilty to seditious conspiracy charges.

The Oath Keepers even discussed a naval operation to ferry in guns to the militia. One Oath Keeper, Thomas Caldwell, asked fellow members if anyone had a boat that could handle crossing the Potomac River. “If we had someone standing by at a dock ramp (one near the Pentagon for sure) we could have our Quick Response Team with the heavy weapons standing by, quickly load them and ferry them across the river to our waiting arms,” the documents quoted him as saying.

Rhodes went on a buying spree in the days leading up to the attack, spending more than $20,000 on guns and equipment for the attack. In December Rhodes bought two pairs of night-vision goggles and a weapons sight for about $7,000 and shipped them to Virginia. In January he spent another $5,000 on a shotgun, scope, magazine, sights, optics, a bipod, a mount, a case of ammunition and gun cleaning supplies. Two days later he spent $6,000 more, and then about $4,500 the next day.

In group chats the Oath Keepers discussed how their quick reaction force (QRF) teams would set up at the Comfort Inn in Ballston Arlington, Virginia, to “use as its base of operations for January 6, 2021”. They reserved three rooms; one was occupied by the so-called North Carolina “QRF” team while Arizona and Florida “QRF teams” stayed in the two others. They used the hotel rooms to store firearms and ammunition.

“It’s easy to dismiss a lot of what is in the indictment as fantasy, as projection of what the Oath Keepers would like to see, but the events of January 6 remind us that these things can become reality very quickly,” said Devin Burghart, executive director of Institute for Research & Education on Human Rights, a group that monitors far-right extremist groups.

“The dangers are there irrespective of their ability to bring all of their fantasies to fruition,” said Burghart.

The planning for some kind of operation appeared to begin right after the election last November, as Trump baselessly disputed the results of the election. Two days after the election Rhodes invited some members of the Oath Keepers to a group chat on Signal, an encrypted messaging app, that was titled “Leadership intel sharing secured”.

Rhodes texted the group: “We aren’t getting through this without a civil war. Too late for that. Prepare your mind, body and spirit.”

On 7 November 2020, when Trump was finally projected to have lost the election, Rhodes began plotting, texting the group chat: “We must now do what the people of Serbia did when Milosevic stole their election. Refuse to accept it and march en-mass on the nations Capitol.” Rhodes then shared a video on Bitchute, an alt-tech video platform, of a step-by-step procedure of how to overthrow a government based on the Serbian example.

Two days later Rhodes held an online conference with Oath Keepers members outlining a plan to overturn the election. Two days later after that a member of the group, Caldwell, reached out to Rhodes to share the results of a “recce” – a military colloquialism for reconnaissance operation – to Washington and begin planning for an upcoming “op” to the Capitol.

From there members began working together. In late November, the Florida chapter of the Oath Keepers held a training on “unconventional warfare”. “It will be a bloody and desperate fight. We are going to have a fight. That can’t be avoided,” Rhodes wrote in a group chat with members in December.

On 21 December 2020, Oath Keepers mentioned January 6 for the first time. James Wakins, one of the 11 Oath Keepers charged in the case, texted the signal chat about a “National call to action for DC Jan 6th” and said Oath Keepers from three states were mobilizing “Everyone in this channel should understand the magnitude of what I just said,” Wakins wrote.

Rhodes told a regional Oath Keeper leader that if Biden assumed the presidency, “We will have to do a bloody, massively bloody revolution against them. That’s whats going to have to happen.”

At 6.27am on the morning of January 6 Rhodes texted the group chat: “We will have several well equipped QRF’s outside D.C.” At about 8.30am Rhodes and other Oath Keepers left from their hotel and drove to the Capitol in Washington DC.

The teams that stayed behind in a hotel in Virginia discussed the possibility of “armed conflict” and “guerrilla war”.

At the Capitol, Oath Keepers marched in formation wearing tactical gear including protective vests, helmets and eye goggles as they carried radios, chemical sprays and hard-knuckle gloves. In the group chat one member shared the rumor that it was leftwing groups that had breached the Capitol. “Nope I’m right here, these are Patriots,” replied Rhodes.

Rhodes never entered the Capitol, but other members of the Oath Keepers did. Jessica Watkins texted in one of the Oath Keepers group chats: “We are in the main dome right now. We are rocking it. They are throwing grenades, they are freaking shooting people with paint balls. But we are in here.” Another member replied with enthusiastic expletives that this what they “trained for”.

The indictment reads that Watkins and other Oath Keepers in one formation joined a mob pushing against a line of law enforcement officers in a hallway containing the Rotunda to the Senate chamber, Watkins commanded those around her to “Push, push, push … get in there, get in there.”