Kennedy dynasty has filed a motion to stop Trump’s arch from obscuring JFK Eternal Flame and slain family gravesites.

Members of the prominent Kennedy family have filed a legal motion to halt the construction of US President Donald Trump’s 76-metre (250ft) “triumphal arch” in Washington, DC, arguing it mars the area near the graves of the family’s famous forebears.

On Tuesday, the nine plaintiffs, children and grandchildren of former Senators Robert F Kennedy and Edward M Kennedy, filed a motion to intervene and an accompanying complaint in two existing federal lawsuits to block the arch’s construction.

The project would sit near the final resting places of the late senators, buried alongside their brother, former President John F Kennedy, and the Eternal Flame commemorating him at Arlington National Cemetery.

Plaintiffs argued the proposed arch would “fundamentally alter the experience of visiting the gravesites”, a site that draws millions of visitors each year.

The intervention motion was filed by veteran Washington lawyer Norm Eisen and Democracy Defenders Fund, a centre-left legal advocacy group.

It contends that the National Park Service and the Department of the Interior authorised the granite, gold-ornamented structure, dubbed the “Arc de Trump” by critics, without required congressional approval.

The plaintiffs also argue the megastructure would destroy the intentionally designed, century-old line of sight between the Lincoln Memorial and the cemetery’s Arlington House across the Memorial Bridge.

Many plaintiffs

The high-profile intervention adds to an already sprawling roster of plaintiffs who have launched legal challenges against the polarising monument, including Vietnam War veterans, a historian, and the governments of the District of Columbia, Virginia and Arlington County.

Last week, District Judge Tanya Chutkan prohibited the Trump administration from breaking ground on the structure for another 14 days following the string of lawsuits.

Building the arch would be a “permanent denigration” of the gravesites, and the Kennedy offspring “would never again be able to appreciate both sites as they always have before, and as the Kennedy family always intended”, lawyers for the relatives wrote on Tuesday.

The project is just one component of the president’s effort to remodel much of Washington, DC, alongside a historic golf course renovation and threats to demolish the Kennedy Center.

But with Democrats seizing control of Congress in last week’s midterm elections, the overhauls may be set for heightened scrutiny.

Speaking on behalf of the Kennedy family, Rory and Maxwell Kennedy, children of the late senator Robert F Kennedy, said the action is about “protecting sacred spaces that belong to the American people”. They said several members of their slain family are “among the more than 400,000 veterans and family members buried or honored on this hallowed ground”.

Health and Human Services Secretary Robert F. Kennedy Jr, a Trump appointee who is estranged from much of his family,  did not join the litigation.