A panel led by Trump appointees could give the project the go-ahead on Thursday. As a federal panel prepares to grant final approval to President Donald Trump's "triumphal arch" -- with construction potentially beginning Thursday -- the Vietnam veteran who's leading the lawsuit to stop the project called it "frankly blasphemous." Michael Lemmon, who served in the Army before spending a career in the foreign service, told the National Capital Planning Commission (NCPC) that the arch would "profoundly disturb the peace and tranquility" owed to those buried at nearby Arlington National Cemetery. "It is frankly blasphemous," Lemmon told the commission.

Lemmon was one of 130 people expected to provide their comments to the NCPC before its final vote at a meeting that was taking place entirely online and was likely to last into the evening. The commission, which is led by Trump appointees, is expected to take its final vote approving the arch after all the speakers have provided their testimony.

The proposed arch would be more than twice as tall as the 99-foot-high Lincoln Memorial and taller than France's Arc de Triomphe.

The public testimony began with a fiery exchange between Rep. Jared Huffman of California, the top Democrat on the House Natural Resources Committee, and NCPC Chair Mark Paoletta.

Huffman blasted plans for the arch, saying it "would dishonor America, our ideals and our laws." Paoletta challenged Huffman on his knowledge of the history of Columbia Island -- where the arch would be built across the Potomac River from the Lincoln Memorial -- insisting the project was authorized over 100 years ago when Congress approved the initial plan for Memorial Bridge, which connects Washington, D.C., with the cemetery.

"If you want to make that argument to a federal court, go for it.

You're going to lose," Huffman responded.

A lawsuit filed by Lemmon and fellow vets, recently joined by D.C. and Virginia, accuses the Trump administration of violating federal law by not seeking specific congressional authorization for the project.

Paoletta, a Trump loyalist who also serves as OMB's general counsel and acting head of the Consumer Financial Protection Bureau, defended the arch at the start of the meeting. "President Trump's historic vision for a monumental arch at Memorial Circle would complete a project over a century in the making," Paoletta said, adding that the project would "honor our nation and her veterans, and provide the sacred ground of Arlington National Cemetery with the monumental gateway it deserves."

Pointing to President Trump's plan to have the arch house drones, snipers and ammunition, Paoletta also said the arch would mark "a generational security opportunity to protect our nation's capital." With the administration indicating it could begin construction as soon as the NCPC grants its final approval, the judge presiding over the lawsuit against the project has ordered the administration to provide the court with at least 30 minutes' notice before any work begins.

Earlier Thursday, the Justice Department informed the court that a construction contractor had prematurely painted lines on the grounds. Pictures of the painted grass were posted by a freelance photographer.

Lawyers for the administration say the contractor "did not have authorization from the National Park Service (NPS) to undertake the line painting," adding that NPS officials might "periodically visit the site to prevent unauthorized activity." The Park Service plans to have construction of the arch take place 20 hours per day over the next two to three years, according to planning documents released earlier this year by the Interior Department.