Family members of those killed at the World Trade Center (search) are balking at plans to add a museum of freedom at ground zero, arguing it would allow politics to infect a place revered as sacred.

Relatives representing 14 family groups rallied at the site Monday to condemn plans for the International Freedom Center (search), which officials said would place the 2001 terror attacks in a historical context.

The center would be part of a cultural complex set to open in 2009 at the northeast end of the rebuilt trade center site. It would host discussions on historical and current events, exhibits on global freedom movements and a service program encouraging activities that could range from joining the Peace Corps (search) to enlisting in the U.S. military.

According to the International Freedom Center's Web site, the museum will "deal with the international impact of September 11," as well as such issues as segregation in America and the Holocaust.

"It doesn't belong at a memorial," said Charles Wolf, whose wife, Katherine, died in the World Trade Center collapse. "You wouldn't put a debate about Nazism and authoritarianism at Dachau."

Center President Richard J. Tofel (search) said that while the causes of the Sept. 11 attacks would not be up for debate, the center would not bar criticism of the United States and its actions.

"Part of the way we celebrate freedom is to acknowledge that even the greatest societies in the world and those that have made the greatest contribution to freedom are not perfect," he said.

The center's use of advisers that include some critics of U.S. policy has prompted criticism from conservative commentators in recent weeks.