Members of the Kennedy family are seeking to join a federal lawsuit challenging President Donald Trump’s proposed Independence Arch near Arlington National Cemetery, arguing that the enormous monument would obstruct views of family gravesites and the Eternal Flame.

Nine children and grandchildren of Robert F. Kennedy and Edward M. Kennedy filed a motion Tuesday asking to intervene in the litigation. Their 27 page filing challenges the administration’s plan to build the arch at Memorial Circle near the cemetery in Washington.

The filing portrays the project as a direct threat to the cemetery’s memorial landscape. “President Donald J. Trump is attempting to unlawfully erect a massive arch that will permanently cast shadows over and damage historically significant sightlines to the existing gravesites and memorials established in the Kennedy family’s honor at Arlington National Cemetery, as well as to the memorials of hundreds of thousands of fallen American heroes,” the filing said.

Trump’s proposed monument would stand at least 250 feet tall. That would make it more than twice the height of the Lincoln Memorial, giving the planned structure a considerable presence near the cemetery and its existing memorials.

The Kennedy relatives argue that the arch would disrupt a historic sightline designed to symbolize national reunification after the Civil War. They also contend that the proposed location would interfere with views of the Kennedy gravesites and the Eternal Flame.

Their attorneys wrote that the family has a “particular interest in protecting the Kennedy Gravesites” as a memorial to its legacy. The relatives are asking the court to recognize that interest by allowing them to participate directly in the ongoing litigation.

The family’s motion arrives while construction is already temporarily blocked. U.S. District Judge Tanya Chutkan has prohibited construction of the arch through at least next week as the legal challenges continue.

That order gives the court time to consider the disputes surrounding the planned monument. The Kennedy family’s request adds another group of parties seeking a formal role in the fight over whether the project may proceed.

The filing came days after the National Capital Planning Commission approved the administration’s plans for the arch on Nov. 5. That approval did not end the controversy, as several lawsuits challenging the project were already moving through federal court.

The project faces multiple legal challenges, including a lawsuit filed by private plaintiffs in February. Those plaintiffs are already contesting the administration’s plan, but the Kennedy relatives argue that the existing parties may not adequately represent the family’s particular concerns.

The District of Columbia and Virginia filed separate lawsuits on Oct. 31. A federal judge consolidated those two cases on the same day, bringing their challenges together as the broader legal fight over the arch developed.

For the Kennedy relatives, the dispute is closely connected to the burial sites of their parents and grandparents. The filing identifies former President John F. Kennedy, Robert F. Kennedy and Edward M. Kennedy among the family members buried at Arlington National Cemetery.

The relatives argue that the monument threatens those burial sites and the memorial setting surrounding them. Their concerns focus not only on the arch’s proposed height, but also on the shadows and damage to sightlines that they say the structure would create.

The family also maintains that its interests are distinct from those of the plaintiffs already pursuing challenges. That argument is central to the request to intervene, since the relatives say the current parties may not sufficiently protect the Kennedy gravesites and memorials.

According to the filing, the existing plaintiffs have taken no position on the Kennedy family’s request to join the case. The defendants, meanwhile, have not provided a “substantive response” to the relatives’ effort to intervene.

The court must now consider the family’s request while the temporary block on construction remains in place through at least next week. The motion places the Kennedy gravesites, the Eternal Flame and the cemetery’s historic sightlines at the center of the legal challenge to Trump’s proposed 250 foot monument.