After Chick-fil-A President Dan Cathy recently made comments expressing his opposition to gay marriage and activists highlighted his foundations' contributions to like-minded groups, two big city mayors -- Rahm Emanuel of Chicago and Thomas Menino of Boston -- weighed in on the issue and threatened to keep the fast food chain from expanding in their communities.

The debacle raised an interesting question: Can -- and more, importantly, should -- a mayor block a business based on the political beliefs of its executives?

Boston Mayor Thomas Menino wrote a letter to Cathy urging him to back out of plans to open a restaurant in the city. "There is no place for discrimination along Boston's Freedom Trail and no place for your company alongside it," he wrote. Then, according to the Boston Herald, he warned, "if they need licenses in the city, it will be very difficult -- unless they open up their policies."

By Thursday, Menino had dialed back his rhetoric, saying he would use his position of power but not any government authority to block the restaurant. He said blocking the restaurant would interfere with its rights, which he wouldn't do. "I make mistakes all the time," he told the Herald. "That’s a Menino-ism."

John Malcolm, a senior legal fellow with the conservative Heritage Foundation, writes in his blog that there's not much of a debate about whether public officials can block businesses based on the political beliefs of its executives, noting that the Supreme Court has already ruled on a similar issue.

"While a government official may deny a business permit (or take any number of other official actions) for non-discriminatory, relevant reasons, he may not do so because he doesn’t like things that the applicant has said," Malcolm writes.

Meanwhile, Chicago Mayor Rahm Emanuel has said that he would work to stop any attempt by Chick-fil-A to expand in the city.

“Chick-fil-A’s values are not Chicago values. They’re not respectful of our residents, our neighbors and our family members. And if you’re gonna be part of the Chicago community, you should reflect Chicago values,” Emanuel told the Chicago Sun-Times.

Chicago Alderman Joe Moreno, whose office had been negotiating with the company over a new location in his ward, pledged to block the restaurant from being approved after Cathy's comments. Matt Bailey, Moreno's spokesperson, tells Governing that Chick-fil-A's corporate opposition to gay marriage had come up during discussions about the company's application, and Moreno believes its executives and attorneys misrepresented their position.

"They said they weren't political. So when we heard the comments from the CEO last week, we realized they were basically just paying us lip service," Bailey says. "They weren't upfront with us."

Moreno decided that the proposal should be denied -- not just because of Cathy's political beliefs but also because of traffic congestion issues.

And in New York City, Mayor Michael Bloomberg said on his radio address Friday that he won't urge the city to ban the food chain and called government-led efforts to do so "a bad idea," the Wall Street Journal reports. "You can’t have a test for what the owners’ personal views are before you decide to give a permit to do something in the city," he reportedly said.

The  American Civil Liberties Union (ACLU) is taking the side of Bloomberg. Adam Schwartz, senior attorney for the ACLU of Illinois, tells Fox News that it opposes the idea of denying permits to Chick-fil-A because if the government in a liberal community can block businesses that oppose gay marriage, then it sets a precedent that governments in conservative communities could block businesses that support gay marriage, he explained.