It’s official: The University of Chicago can use city park land for its bid for the Obama Presidential Library.

The Chicago City Council signed off on Mayor Rahm Emanuel’s proposal to allow the university use of about 20 acres of land on the South Side in Washington Park or Jackson Park, should the president chooses the U of C bid for the coveted library. The proposal was Emanuel’s way of soothing any anxiety the Obama Foundation had about the Hyde Park-based school’s bid; or, as he calls, it, moving “heaven and earth” to make sure the library lands in Chicago.

Emanuel called the library a “once-in-a-lifetime opportunity” for the city.

“If you have another [project with] half-a-billion dollar to three-quarter-of-a-billion dollar economic impact,” Emanuel said. “I have a suggestion box, could you please put it in? I have yet to see it.”

Back in January, the Obama Foundation raised concerns over the city’s lack of control over the proposed sites in the University of Chicago bid. Emanuel’s land transfer would allow either park to be used, and in exchange, promises the Chicago Park District will receive additional green space.

On Wednesday, aldermen from all over the city stood up, one-by-one, in support of not just the park land proposal, but to share once again why they believe the library belongs in Chicago.

“Whether it’s Jackson Park or Washington Park or North Lawndale, there’s an opportunity to bring thousands of jobs, $750 million investment in communities that have not been invested in for years,” Ald. Will Burns (4) said.

Others stressed Obama’s Chicago roots and his connection to the South and West Side communities.

“Every political decision that the president made, I was there with him,” Ald. Leslie Hairston said. “His roots are right there in Hyde Park, in the 5th ward.”

The vote total almost ended with one dissenter: On the first roll call vote, Ald. Bob Fioretti (2nd) voted against the plan. But after some prodding from his colleagues, and a nod from Mayor Emanuel that any hiring for the library plan would come from the neighborhoods, he switched to a Yes vote.

But even with a strong vote total out City Hall, it will be the president and first lady who makes the final decision about where the library lands. The Obamas could choose Columbia University in New York City, the University of Hawaii or the University of Illinois at Chicago. According to multiple news reports, that decision isn’t expected to come until after Chicago’s mayoral runoff election.

There is opposition to the park land plan outside of the council chambers: The Friends of the Parks group has long said that the mayor’s proposal could set a “dangerous precedent” and that it has national parks groups watching. The group hasn’t ruled out any potential legal action.

Lauren Chooljian is a WBEZ political reporter. Follow her @laurenchooljian.