A key state lawmaker wants more green for the Greenway. Or else.

Representative Aaron Michlewitz is suggesting the state could thwart the billion-dollar Winthrop Square skyscraper project if the city of Boston doesn’t agree to put some of the money it would make from the development toward maintaining the Rose Fitzgerald Kennedy Greenway, the park that snakes through the heart of the city.

The North End Democrat, whose district encompasses both the park and the defunct garage that Millennium Partners wants to turn into a 700-plus-foot tower, said Boston should give an unspecified amount of its expected windfall from the project for maintenance of the 17-acre park.


Michlewitz is part of the Democratic leadership in the House of Representatives, which, along with the Senate, will need to approve a change to the state’s law on shadows on the Boston Common if the project is to move forward. The tower would cast a big shadow and thus needs special approval. The House is run tightly, so it is unlikely Michlewitz would speak without at least a tacit OK from Speaker Robert A. DeLeo or his confidants.

Michlewitz emphasized that he has not yet decided whether he will support the new building. Asked whether his support is contingent on the city giving money to the Greenway, Michlewitz paused for several seconds. Boston giving money to the park “would be an important selling piece for my constituents” and thus for him to back the tower project.

“I think it’s paramount that we preserve our history in places like the Boston Common,” he said. “At the same time, we need to be promoting the future with places like the Greenway, which has become, without a doubt, an essential and vibrant part of our community.”

Massachusetts owns the park and contracts with the nonprofit Greenway Conservancy to run the popular open space.


But the state is set to pull the plug on millions of dollars in funding for the nonprofit at the end of June. And that’s led people with a stake in the future of the park to scramble for new funding sources, aiming to fill what could be a $2 million-a-year hole.

The city has always been ice cold to the idea of picking up the tab for a state-owned park. What’s next, the thinking goes; will Boston have to pay for the state-owned Esplanade, too?

“Mayor Walsh hopes that the state and the Greenway can reach a fair resolution that maintains what has become a treasured state asset that is enjoyed by people from around the Commonwealth and the world,” a spokeswoman for the city said this week.

Millennium Partners has agreed to pay Boston $153 million for rights to build on the garage site. City officials are calling the deal a “once-in-a-generation opportunity.” They’ve already publicly earmarked $102 million in proceeds from the sale, including $28 million for upgrades to Boston Common, $28 million for Franklin Park, $25 million for more redevelopment of the Old Colony public housing complex in South Boston, and $10 million in ongoing improvements at the Orient Heights public housing complex in East Boston.

But the remaining $51 million won’t be coming into city coffers until condos in the tall tower are sold, so that could not be used to bridge any potential gap in Greenway funding if the state stops giving the Conservancy money this summer.


Still, Michlewitz said the earmarks aren’t set in stone and some of that cash should go to maintain the Greenway. He argues that the Greenway is an economic engine for the city, so the city should help pay for it.

Michlewitz, who is the House chairman of the powerful Joint Committee on Financial Services, did not offer a specific amount of money but said it should help keep the park well-maintained until a long-term, permanent funding solution is in place.

“We have to figure out a long-term mechanism about how the Greenway will be supported, and I don’t think that mechanism is in place today,” he said.

Michlewitz also floated the possibility of the developer, Millennium Partners, contributing money directly to the Conservancy to help bridge any funding gaps that might result from a diminution of state support.

Millennium Partners did not respond to a request for comment.

The Greenway has an endowment of $13.5 million, whose returns also help support the park. Since 2009, the state has contributed more than $15 million to the Greenway, according to data from the state comptroller. But officials have repeatedly warned the nonprofit can’t rely on the state’s largesse forever.

Those warnings grew sharper after an outside group accused the nonprofit last year of mismanagement and superfluous spending. The Conservancy launched an internal investigation into those allegations and deemed them unfounded.

Both the City Council and the Legislature will need to approve the change in the Boston Common shadow requirements for the tower project to move forward.


Walsh has not yet filed a formal proposal to the City Council, but aides say that will happen soon.

Seth Gitell, a spokesman for DeLeo, the speaker, said the House hasn’t received any legislation on the matter, and will look at any bills it gets.

Tim Logan of the Globe staff contributed to this report. Joshua Miller can be reached at joshua.miller@globe.com. Follow him on Twitter @jm_bos and subscribe to his weekday e-mail update on politics at bostonglobe.com/