NEW YORK, NY.- Debates over antisemitism have flared for months on college campuses, in local government meetings and in Congress, in many cases boiling down to bitter disagreements over what is, and what is not, antisemitism.

There was no such argument 5 1/2 years ago in Pittsburgh. When 11 worshippers were killed at the Tree of Life synagogue Oct. 27, 2018, the gunman who carried out the massacre was blunt in his bigotry, declaring beforehand on social media that he was acting out of a conviction that Jewish people were conspiring to replace the white race.

On Sunday, members of the Tree of Life congregation will gather to break ground for a memorial and a new Tree of Life building. The airy, angular structure, designed by architect Daniel Libeskind, will house a sanctuary for the Tree of Life congregation — one of three congregations meeting at the synagogue at the time of the shooting — an education center dedicated to combating bigotry and a museum chronicling the long history of antisemitism in America.

It is a story that has gotten more complicated to tell since the Hamas-led attack on Israel on Oct. 7 and the war that has followed.

“It makes our job harder, and I’m sure we’re going to have to wade into some fairly difficult waters,” said Michael Bernstein, the chair of the Tree of Life board of directors. But “that is the point of what we have to do,” he added, “to allow people to engage in this much more deeply.”

The museum will be the first in the United States dedicated exclusively to the history of antisemitism in America, from the colonial days through the hard-line anti-immigrant politics of the mid-20th century to the neo-Nazi march in Charlottesville, Virginia, in 2017, and beyond. The museum will show how the mass shooting at Tree of Life was an especially dark day, but nonetheless part of an old affliction in America.

“We need to go through that story to get to the kind of narrative arc to where an event like this can happen, and be understood,” said Ralph Appelbaum, who designed the museum and whose firm designed the U.S. Holocaust Memorial Museum in Washington and galleries at the International African American Museum in Charleston, South Carolina.

This will be different from many of his other projects, Appelbaum said, primarily because of where it is: “one of the rare instances that we have in America of building something on a site of such violence, where the context is clear and not historical.”

The motive for that violence was indeed clear, explained by the killer in hate-filled rants on social media. Pittsburghers of many different faiths rallied to support the survivors and denounce the antisemitism behind the attack. The phrase “stronger than hate” quickly became a mantra for the whole city.

But recently, that kind of unity has been in short supply.

Debates over the Hamas-led terror attack and Israel’s military response in Gaza have tested and broken old alliances, forcing many people to take a position on whether or when opposition to the Israeli government’s actions becomes synonymous with antisemitism. There are disagreements about this within the Jewish community and even within the Tree of Life congregation. How the museum would address these matters is among the questions facing the congregation.

Diane Rosenthal, 63, whose brothers Cecil and David Rosenthal were killed in the attack, said the exhibits and programs are in the early planning stages. But she hopes that the museum will play a key role in informing the current debates.

“With what’s going on on campuses, I think education is even more important,” she said. “The rhetoric out there on social media does such a poor job from an Israeli and Jewish perspective. I look at this new institution as a place where people can really get a true education.”

This concerns Alexandra Weiner, 25, a math instructor at the University of Pittsburgh. Weiner has been a member of Tree of Life since she was a child and was on her way to services there on the morning of the shooting. She has also been outspoken against the Israeli government on her campus, with her criticism drawing complaints from pro-Israel groups and at least one Jewish student.

She fears that the museum will be pressured to adopt a definition of antisemitism that does not allow for a critical view of the politics of Israel.

“I’m very worried about what a museum about the history of American antisemitism would look like at Tree of Life,” she said. “And I think that’s incredibly sad.”

Those in synagogue leadership, as well as some of the academic advisers who have been brought on to help shape the museum, said the new institution was not envisioned as a place that would deliver definitive answers on heated public questions. The museum will provide historical context, and the education center will be a place where difficult questions can be debated and discussed.

It is “more to be a space that honors and explores these complicated issues,” said Carole Zawatsky, the CEO of Tree of Life.

She and other officials pointed out that focusing only on issues in the most recent headlines would miss other dangerous expressions of antisemitism in the country festering outside public view. There was, after all, a long history behind the hatred harbored by the Tree of Life gunman, who was convicted last summer and sentenced to death. But in 2018, no one realized the threat he posed to the synagogue and the deeply rooted Jewish community around it.

“I think we see what happens,” Zawatsky said, “when the public forgets too quickly.”

This article originally appeared in The New York Times.