White House and agency officials have repeatedly declined to answer whether they will seek authorization for Trump's arch from the current Congress.

Instead, administration officials have cited a 1924 report by a federal commission charged with designing the Arlington Memorial Bridge. That report called for building a pair of 166-foot-tall columns, surmounted by statues, on Columbia Island that would frame the nearby Lincoln Memorial.

Congress formally ratified the commission's report in 1925, and the Memorial Bridge was soon built. However, the columns were not constructed, and Trump officials today argue that in building the arch they would be carrying out past lawmakers' wishes.

"Congress authorized the arch project when it approved the design set out in Arlington Memorial Bridge Commission's report," Justice Department lawyers wrote in a filing last month.