Movie mogul George Lucas has his “heart set” on building a $400 million museum on 17 acres of lakefront land near Soldier Field, Mayor Rahm Emanuel disclosed Wednesday, saying he’s now afraid Chicago will lose the coveted prize.

Emanuel said Lucas’ hometown of San Francisco “coughed it up” after a federal panel rejected the picturesque Presidio site that was Lucas’ top choice.

The mayor said he now fears Chicago will do the same, thanks to a federal judge’s decision to keep alive a lawsuit filed by Friends of the Parks challenging the lakefront land giveaway.

“We have a lawsuit. Other cities are not going to wait for that lawsuit to play itself out. We have that as a challenge for us,” the mayor said.

“This is a family that’s willing to donate hundreds of millions of dollars to fulfill our vision as a city — not mine. … I just hope that, as the other cities compete, that we do not lose a tremendous charitable donation. … Other cities now are competing for their hearts and their resources. … We don’t stand alone. In the past, it was San Francisco’s to lose and they lost it. I do not want to lose this for Chicago. My goal is to keep it here, but there are other cities competing for it now. … I hope we don’t lose it.”

Weeks after opening the door to a site change to avoid a protracted legal battle, Emanuel hinted strongly that his efforts to persuade Lucas and his wife, Chicago businesswoman Mellody Hobson, to consider another site have either failed or are not going well.

“You have to speak to them. I would just say it’s only human to have your heart kind of set on something, given that a task force made a recommendation. The Park District made changes. The Chicago Bears made changes. The state Legislature passed a law. All part of a vision set out decades ago of a museum campus. This fulfills it, taking a parking lot and turning it into open space and a cultural museum,” Emanuel said.

“I want it in the city of Chicago. I’m obviously strong about Chicago. [But] the task force made a recommendation. They liked it. … I can’t just tell ’em and I’m never going to [to accept another site] The task force did a study. They made a recommendation. They agreed to it. … So we will continue to work. But, it’s not for me alone to make that decision.”

The mayor refused to identify alternative sites under consideration.

Friends of the Parks has urged Lucas to consider building his museum at the old Michael Reese hospital site acquired by the city for an Olympic Village or on the west side of Lake Shore Drive on a deck above rail yards similar to the one that holds Millennium Park.

Ald. Susan Sadlowski-Garza (10th) has urged Lucas to build the museum that will house his formidable collection of artwork and movie-making memorabilia on the site of the old U. S. Steel South Works plant after a split between the steel giant and a prominent Chicago developer killed plans for a “new city” on the long-vacant site.

Chicago has been in danger of losing the Lucas Museum ever since a federal judge last month rejected the city’s motion to dismiss the lawsuit filed by Friends of the Parks.

Technically, U.S. District Judge John Darrah’s ruling merely kept the lawsuit alive. But, his strongly-worded ruling lent new credibility to the group’s claim that a 99-year lease “effectively surrenders control” of prime lakefront property to the museum.

Friends of the Park contends, and Darrah agrees, that the museum “is not for the benefit of the public,” but would “promote private and/or commercial interests.”

Darrah allowed the suit to proceed despite an 11th-hour fix that Emanuel muscled through the Illinois General Assembly that was tailor-made to eliminate the lawsuit’s central argument.

Tucked into legal protections for the Obama presidential library was language that also allows construction on formerly submerged land that was once part of Lake Michigan. But Darrah said Friends of the Parks made a compelling argument that the legislation was not sufficient to turn the land over to the museum.

Friends of the Park now expects to depose city officials about the deal.

A bench trial in the case had been set for March 14, but now it will not likely occur before fall.

At a hearing in the case Wednesday, Darrah also took city attorneys to task, telling them the controversy could have been resolved much sooner if not for their own delays — including a bid to lift his order preventing work from starting at the site.

The judge reviewed the history of the case and told the two sides to return next week with a plan for how it should move forward. He said previous schedules proposed by the city were “manifestly unfair,” and he said “the consequences of doing this wrong are severe.”

Attorneys for both sides told Darrah a new schedule had been agreed upon.

Ever since Darrah’s ruling to allow the lawsuit to proceed, there has been rampant speculation that Lucas would take the museum elsewhere.

The Star Wars creator had hoped to begin construction in the spring or early summer and that timetable will not be possible now.

When Lucas considers the deposition, discovery and legal fees, and the very real possibility that Friends of the Parks could actually win, he might just throw in the towel.

Lucas’ hometown of San Francisco and Los Angeles would like nothing more than to snatch the coveted project.

Further complicating the issue for Lucas is the fact that Emanuel, the project’s biggest champion, has been weakened considerably by his handling of the Laquan McDonald shooting video.

When Emanuel engineered the giveaway of prime lakefront land, he was at the height of his political power. He was easily able to ram the controversial project through the Chicago Park District Board, the Chicago Plan Commission and the City Council and persuade the Illinois General Assembly to make the 11th-hour legal change.

Now, Lucas can rightfully question whether Emanuel has the juice to get the project done. That’s especially true now that the legal battle is likely to drag on through a second term in office that is almost certain to be Emanuel’s last — either because he’s unelectable or because he chooses to call it quits.