Nine members of the Kennedy family sought permission Tuesday to join two lawsuits challenging President Donald Trump’s proposed triumphal arch, telling a federal judge in Washington that the project would affect their relatives’ graves at Arlington National Cemetery. Their request adds the family’s objections to a legal fight that has already halted construction.

The proposed structure would rise 250 feet on Memorial Circle, between Arlington National Cemetery and the Lincoln Memorial, making it more than twice as tall as the Lincoln Memorial. The family argues that it would cast shadows across Kennedy burial sites and interrupt the unobstructed view from the John F. Kennedy Eternal Flame memorial, across Arlington Memorial Bridge, to the Lincoln Memorial. They describe that view as integral to the memorial’s design.

Seven of Robert F. Kennedy’s living children are among the relatives seeking to enter the litigation. Health Secretary Robert F. Kennedy Jr. is the only one of his living children who is not participating. Members of the family buried at Arlington include President John F. Kennedy, first lady Jacqueline Kennedy Onassis, Attorney General Robert F. Kennedy and Sen. Ted Kennedy.

In a joint statement, Rory Kennedy and Maxwell Kennedy described their effort as a matter of “protecting sacred spaces.” They accused Trump of disregarding laws and procedures Congress established to safeguard the memorial. They also argued that an arch overshadowing the graves of their parents, uncles and others who served the country would undermine the democratic protections intended to preserve the site for future generations.

The existing lawsuits were brought by the District of Columbia and Virginia, and by Michael Lemmon, a Vietnam War veteran and former U.S. ambassador. The Kennedy relatives asked to participate in both cases, saying they have an immediate stake in the outcome and share legal questions with the existing plaintiffs. Their filing emphasizes their particular interest in preserving the family gravesites as solemn places of remembrance.

A federal judge stopped construction last week, shortly after a planning board composed mostly of Trump-aligned members approved the project. The dispute follows another confrontation involving Trump and the Kennedy family over his efforts to reshape the Kennedy Center. Trump closed the arts institution after a judge prevented him from putting his name on the building.

White House spokesperson Davis Ingle said the administration expects to prevail in court. He expressed disappointment at the relatives’ involvement, saying the arch is intended to honor those buried at Arlington. Ingle also argued that the litigation was politicizing a project the administration views as a means of bringing the country together.