Earlier this week Trump announced that the proposed “Triumphal Arch” would double as a complex to store military equipment, complete with the ability to deploy snipers and drones from the roof and plaza.
In a letter to the Pentagon and Federal Aviation Administration (FAA), Duckworth said they “must reject this foolhardy plan and instead focus on increasing the safety of the airspace”.
The arch is to be built just outside Arlington National Cemetery in Virginia, and about 4mi (6km) from Ronald Reagan Washington National Airport, the site of the deadly 2025 midair crash between a military helicopter and commercial plane.
“The American people cannot afford to stand witness to Trump’s risky plan to place a 250-foot (72m) structure along a busy approach path, especially if he follows through on plans to station snipers on the arch and fly drones,” Duckworth wrote in the letter, which was obtained by the BBC’s US partner, CBS News.
The FAA, however, ruled last week that the massive structure would not pose a risk to flights coming into and out of the airport.
On Thursday, the Advisory Council on Historic Preservation, led by Trump appointees, announced it was ending required consultations with local officials about how the structure might affect 42 historic properties in the area.
The council said in the announcement that the National Park Service, which oversees federal landmarks, had proposed a plan for mitigating potential harms to those properties, but local historic preservation officers “raised concerns with the purpose and need of the Triumphal Arch”. They also questioned whether the service had adequately identified possible harms and planned sufficient actions to address them.
Federal and state officials are not required to reach an agreement on a project’s harm-mitigation plans, and those consultations are allowed to be terminated if both sides can’t agree. The council expects to submit a final report on the process early next month.
Meanwhile, Democratic Virginia Congressman Don Beyer says excavation work on the site where the arch will stand has already begun.
Beyer, who is leading congressional opposition to the arch, said he found workers operating heavy equipment when he visited the site on Thursday who told him they were “conducting archaeological work to evaluate the composition of the soil”.
That is “deeply troubling”, Beyer said, particularly because the administration is required to give 48 hours notice before work can begin.
“The Administration appears to be pushing ahead with activity at the site even while it still has not done the basic work necessary to understand the consequences of this project,” Beyer wrote.
A rendering of the design from earlier this year includes a golden, winged Lady Liberty on the top of the arch, flanked by two gold eagles, and with the phrases “One Nation Under God” and “Liberty and Justice for All” inscribed in gold on either side of the structure.
