NEW YORK — A judge on Friday tossed out a lawsuit that sought to stop the display of a cross-shaped steel beam found among the World Trade Center’s rubble, saying the artifact could help tell the story of the 9/11 terrorist attacks.

U.S. District Judge Deborah Batts rejected the arguments of American Atheists, which had sued the National September 11 Memorial & Museum’s operators in 2011 on constitutional grounds, contending that the prominent display of the cross constitutes an endorsement of Christianity, diminishing the contributions of non-Christian rescuers.

Batts wrote that the cross and its accompanying panels of text “helps demonstrate how those at ground zero coped with the devastation they witnessed during the rescue and recovery effort.” She called its purpose “historical and secular” and noted that it will be housed at the museum in the “Finding Meaning at Ground Zero” section with placards explaining its meaning and the reason for its inclusion. It also will be surrounded by secular artifacts.

“No reasonable observer would view the artifact as endorsing Christianity,” the judge said. She added that the museum’s creators “have not advanced religion impermissibly, and the cross does not create excessive entanglement between the state and religion.” She said the plaintiffs also failed to allege any form of intentional discrimination or cite any adverse or unequal treatment on the basis of their religious beliefs.

The 17-foot-tall steel beam was found by rescue workers two days after the terror attacks. It is scheduled to be displayed among 1,000 artifacts, photos, oral histories and videos in an underground museum that will also house the staircase workers used to escape the towers as well as portraits of the nearly 3,000 victims and oral histories of Sept. 11. The museum, still under construction and scheduled to open next year, is part of a memorial plaza that includes waterfalls that fill the fallen towers’ footprints.

A lawyer for the atheists group did not immediately respond to a request for comment.

Joe Daniels, the museum’s president, said he was grateful that the court “agrees that the display of the World Trade Center Cross is not a constitutional violation but is in fact a crucial part of the 9/11 Memorial Museum’s mission of preserving the true history of 9/11.”

Attorney Mark Alcott, who represented the museum, said the ruling will protect the museum’s depiction of the aftermath of the attacks.

“It was not intended to and will not promote any religion or discriminate against any religion,” he said.