Lucas previously committed $300 million to build the museum in San Francisco, with renderings depicting a 95,000-square-foot facility. Lucas has said the museum would receive a $400 million endowment over time. In comparison, Chicago's Adler Planetarium is more than 145,500 square feet, according to its website.
Should Chicago win the museum, Perry said the institution would need to grow in size to make up for the loss of current, off-site storage in San Francisco. He also said previous architectural renderings would be tossed and the design process would start anew.
"I really do want to stress from the beginning, we're not trying to play funny with words and say we may come back at you for this tax, or for this request for money," Perry said. "This is a gift of philanthropy in the style of a Rockefeller, a Carnegie, a Mellon or a Smithson (the founding donor of the Smithsonian Institution). This is a sort of once-in-a-lifetime gift of philanthropy that this country hasn't seen from a cultural perspective in many, many decades."
Chicago would seem to have some advantages over San Francisco, namely greater tourism traffic. Chicago set a record in 2012, the most recent year for which annual figures are available, with 46.37 million visitors. Emanuel recently increased the city's goal to 55 million visitors annually by 2020, up from 50 million.
The city of San Francisco attracted 16.51 million visitors in 2012, according to the San Francisco Travel Association.
"I think Chicago has a diversity of communities and level of accessibility that is unparalleled in the country," Spielfogel said. "We've got a larger, more vibrant city that would allow for a bigger audience, and we have a very supportive government who sees the potential for this to help on a local and international level."
Still, Lucas grew up in Modesto, Calif., about 90 miles east of San Francisco. And the city has shaped his life and career.
"I spent my whole young years up until I was in college coming to San Francisco, coming to the cultural events, coming to the baseball games," Lucas said during a September 2013 presentation at a public meeting at the Presidio.
"Back in those days, we had roadshow productions, where the movies were in the big theaters down on Market Street. We even had numbered seats, and I would come and see all the big movies here in San Francisco. And go to the museums. Generally, this, to me, was the cultural center of my life. So when I moved here in 1969, right out of college, I stayed here. And I built my business here. I never made a movie in Hollywood."
After four years of talks with The Presidio Trust, the tone has changed.
When asked whether Lucas still prefers that his museum be built in San Francisco, Perry said: "George Lucas prefers this museum be built for future generations. And I think it's obvious why the first place he looked at was right here in his own backyard. … But he ultimately feels that what is important is that this museum is built someplace where it will add to the educational benefit of young people and where the community embraces it."