A retired U.S. Army colonel who circulated a proposal to challenge the 2020 election, including by declaring a national security emergency and seizing paper ballots, said that he visited the White House on multiple occasions after the election, spoke with President Donald Trump’s chief of staff “maybe eight to 10 times” and briefed several members of Congress on the eve of the Jan. 6 riot.

Phil Waldron, the retired colonel, was working with Trump’s outside lawyers and was part of a team that briefed the lawmakers on a PowerPoint presentation detailing “Options for 6 JAN,” Waldron told The Washington Post. He said his contribution to the presentation focused on his claims of foreign interference in the vote, as did his discussions with the White House.

A version of the presentation made its way to the White House chief of staff, Mark Meadows, on Jan. 5. That information surfaced publicly this week after the congressional committee investigating the insurrection released a letter that said Meadows had turned the document over to the committee.

“The presentation was that there was significant foreign interference in the election, here’s the proof,” Waldron said. “These are constitutional, legal, feasible, acceptable and suitable courses of action.”

The PowerPoint circulated by Waldron included proposals for Vice President Mike Pence on Jan. 6 to reject electors from “states where fraud occurred” or replace them with Republican electors. It included a third proposal in which the certification of Joe Biden’s victory was to be delayed, and U.S. marshals and National Guard troops were to help “secure” and count paper ballots in key states.

Multiple scholars have said there was no legal basis for Pence to intervene in the counting of electoral votes on Jan. 6. Numerous ballot recounts and legal proceedings have confirmed that there was no evidence of any significant fraud in the 2020 election.

Although Trump at the time was pressuring Pence to delay certifying Biden’s victory, it is not clear how widely the PowerPoint was circulated or how seriously the ideas in it were considered. A lawyer for Meadows, George J. Terwilliger III, said on Friday that there was no indication that Meadows did anything with the document after receiving it by email. “We produced it [to the committee] because it was not privileged,” Terwilliger said. A Meadows spokesman, Ben Williamson, declined to comment. Waldron said he was not the person who sent the PowerPoint to Meadows.

Still, Waldron’s account of his interactions with the White House, together with a 36-page version of the presentation that surfaced online this week and was reviewed by The Post, shed new light on the wild theories and proposals that circulated among the people advising Trump as they worked to overturn his election defeat, causing a crisis at the heart of government. They suggest that Meadows, who also pressed senior Justice Department leaders to investigate baseless conspiracy theories about election fraud, was more directly in contact with proponents of such theories than was previously known.

Waldron, a cybersecurity consultant who specialized in psychological operations during his military career, said that a meeting he and others had with Meadows in the days around Christmas turned to questions about how to determine whether the election had been hacked. He said Meadows asked, “What do you need? What would help?” Waldron said his team developed a list for Meadows with information on IP addresses, servers and other data that he believed needed to be investigated “using the powers of the world’s greatest national security intelligence apparatus.”

One person familiar with what Waldron called a “shopping list” confirmed the efforts to assemble it. That person, like some others quoted in this report, spoke on the condition of anonymity to discuss sensitive matters.

Waldron said Meadows indicated that he would pass the list on to John Ratcliffe, then the director of national intelligence, but said he did not know whether Meadows ultimately did. Through a spokesman, Ratcliffe said he did not receive such a document.

One person familiar with the matter confirmed that Meadows met with Waldron at the White House in December, although a person familiar with Meadows’s thinking stressed that Meadows had “little or nothing to do” with Waldron and did not endorse the document. The person said that Meadows’s role, as chief of staff, was often to receive information and pass it along to an appropriate recipient. He said Meadows often did this without endorsing the substance of a given idea or suggestion.

Waldron said that he and Meadows “weren’t pen pals” and that their communication was often through Trump’s personal attorney Rudolph W. Giuliani, who sometimes asked him to “explain this to Mark” over the phone. Giuliani did not respond to requests for comment.

Waldron told The Post that he also attended a Nov. 25 meeting with Trump and several Pennsylvania legislators in the Oval Office. A person familiar with that meeting confirmed Waldron’s presence.

Waldron said he also once briefed Sen. Lindsey O. Graham (R-S.C.) at the White House, in the chief of staff’s office, with Giuliani present. Graham did not respond to a request for comment.

In early January, Waldron was working alongside Trump’s attorneys Giuliani and John C. Eastman from a suite at the Willard hotel in downtown Washington, gathering purported evidence of election fraud, The Post previously reported. Waldron was a supporting witness for Giuliani at hearings on election fraud held by lawmakers in battleground states after the 2020 vote.

Rep. Bennie G. Thompson (D-Miss.), the chairman of the select committee investigating the Jan. 6 attack, said in a letter to Terwilliger this week that Meadows had turned over an email regarding a 38-page PowerPoint presentation “that was to be provided ‘on the hill’,” titled “Election Fraud, Foreign Interference & Options for 6 JAN.” The 36-page presentation reviewed by The Post and which Waldron shared with conservative broadcasters in January has the same title.

Two people familiar with Meadows’s evidence said that he had also turned over the presentation itself and that it was similar in substance to the 36-page presentation. “The overall conclusions are the same, but there are some small differences,” one of the people said. The people were not authorized to discuss the matter publicly.

Having turned over this and other records that his attorneys say encompassed thousands of documents and messages, Meadows has rejected the committee’s demand that he appear for testimony, citing executive privilege. In a lawsuit, he has asked a judge to invalidate the panel’s subpoenas, calling them “overly broad and unduly burdensome.”

The committee plans to vote Monday on a recommendation that the House refer Meadows to the Justice Department for prosecution on a charge of contempt of Congress.

The role played after the election by Waldron is another example of how the president aligned himself with a cast of fringe personalities as he worked to sabotage the U.S. democratic process.

Waldron said in the interview that he traveled to Washington around Nov. 9 or 10, 2020, and first met a few days later with Giuliani and Giuliani’s associate Bernard Kerik, a former New York City police commissioner.

Waldron said he joined the Pennsylvania lawmakers in the Nov. 25 meeting with Trump in the Oval Office. During that period, the president was meeting with legislators from key states and urging them to reject the official vote counts in their states, according to previous reports.

Describing the meeting, Waldron told The Post that Trump “didn’t ask me anything.”

“I was just there. He was more interested in talking to the legislators and understanding what happened in the Pennsylvania elections. … It was very informal. He had a lot of conversation with state legislators and senators and just asked them, ‘What do you think?’ ”

A Trump spokesman did not respond to a request for comment.

Waldron said he went on to brief Sen. Ron Johnson (R-Wis.) and Johnson’s staff ahead of a Dec. 16 hearing on election fraud by the Senate Homeland Security Committee. In a statement to The Post on Friday, Johnson did not directly address whether Waldron had briefed him and his staff. “My staff took meetings from many who could offer their expertise on election security and to hear from those who had concerns about irregularities ahead of my December 16, 2020, hearing,” he said.

Waldron said that on Jan. 5 he was among about a half-dozen people who briefed several members of Congress in a congressional office. He declined to identify the members without their permission and said that others may have joined by video. The members were “shocked” by the presentation but did not commit to any action, Waldron recalled.

Waldron shared the 36-page presentation with the hosts of a conservative podcast and an online talk show later in January and discussed parts of it in interviews with them.

Waldron, 57, who is based in Dripping Springs, Tex., told The Post that before the election, he started working with the Texas company Allied Security Operations Group (ASOG). Russell J. Ramsland Jr., ASOG’s leader, was also photographed at the Willard in the days before the riot, and Eastman told The Post that he met Ramsland around that time. Over the previous two years, the firm promoted claims about the dangers of electronic voting to a procession of conservative lawmakers, activists and donors, The Post has reported.

Ramsland said in an email to The Post that he did not know who put the PowerPoint presentation together or who sent it to Meadows. He did not answer a question about his presence at the Willard or his relationship to Giuliani’s team.

In 2018 and 2019, when Meadows was a congressman from North Carolina, his campaign paid ASOG more than $700 for “security services,” according to campaign finance disclosures.

Waldron served in the Army, Army Reserve, Texas Army National Guard and the Individual Ready Reserve from May 1986 to June 2016 and received multiple service awards, an Army spokesman told The Post last year, adding that Waldron retired as a psychological operations and civil affairs officer. Waldron was deployed to Iraq from 2004 to 2005, the spokesman said.

Waldron has said that the team behind the PowerPoint included former intelligence officers and military veterans and was supported by hundreds of “digital warriors” who provided research. Jovan H. Pulitzer, a Texas-based entrepreneur who is a vocal election denier, told The Post that he contributed material for it.

“It was a pretty wide variety of folks from around this country that jumped in to say how can we help,” Waldron told The Post.

The Waldron team’s 36-page presentation includes several slides that were previously published elsewhere, including graphs purporting to show “vote injections” in key states including Arizona and Pennsylvania.

Some of the graphs appeared in a Nov. 24 blog post by Patrick Byrne, the founder and former chief executive of Overstock.com. The following day, Waldron held up a copy of the Pennsylvania graph when he testified in support of Giuliani at a meeting with state legislators in Gettysburg. Waldron claimed that the graph showed “spike anomalies” that were signs of fraud.

The Arizona graph appeared, with the same design, text and font, in a Dec. 1 affidavit from Ramsland that pro-Trump lawyer Sidney Powell included as purported evidence of fraud in a lawsuit seeking to “decertify” Arizona’s election results.

Waldron noted to The Post that the presentation did not advocate violence as a tactic to delay certification of Biden as winner. “Violence is absolutely the last thing that anybody on our team espoused,” he said.

Since January, Waldron has built a significant following among Trump supporters by continuing to spread false claims about election fraud, including onstage at an August conference hosted by MyPillow CEO Mike Lindell.

Waldron also has promoted the ongoing campaign for “audits” of the 2020 election, including the Republican-commissioned review of 2.1 million ballots cast in Maricopa County, Ariz.

Arizona Senate President Karen Fann consulted Waldron in deciding to hire the Florida firm Cyber Ninjas to conduct that review, according to text messages that the nonprofit American Oversight obtained through a public records request.

Waldron was named in a 2020 state corporate filing as the chief executive of PointStream Inc. of Dripping Springs, which bills itself as a discreet cybersecurity firm. Specialties that PointStream touts on its website include “deep access to the Internet of Things, Social Media, and Dark Web,” conducting untraceable “cyber lurking,” and providing data sets “virtually unknown” to either private industry or the U.S. government.

PointStream was awarded a little over $60,000 in federal contracting in 2018. Spending records show the award was for “highly adaptive cybersecurity services” for the Defense Department’s U.S. Southern Command.

Waldron also has worked as a firearms instructor and owns a distillery, according to a company website and a state corporate filing.

Aaron C. Davis contributed to this report.