Common Cause of Georgia is canvassing the streets in another attempt to force a November vote on Atlanta's plan to help finance the proposed $1 billion Falcons stadium. But city officials say this petition effort, like the first, fails to clear the necessary legal hurdles.

The first petition request — aimed at repealing the March city council resolution allowing the city to commit $200 million in hotel-motel taxes to the project— was denied by the city’s legal department. The department said a 1998 Georgia Supreme Court ruling prohibited the petition.

Common Cause director William Perry said the second petition seeks to amend the city charter to make it illegal to use hotel-motel taxes for the stadium construction project. His group is now trying to collect 35,000 signatures of registered voters within a 60-day window to have the issue placed on a ballot.

But City Attorney Cathy Hampton said the latest effort is also unconstitutional for myriad reasons. For example, the petition seeks to change state law, apply new law to past actions and cancel existing contracts, she said.

Common Cause isn’t discouraged, Perry said.

“Our lawyers completely disagree, so we’re pressing forward in getting signatures. And, if we accomplish that task, we’ll forge ahead and go to court (if necessary),” he said.

Common Cause has been the most vocal opponent of the stadium deal, which in addition to hotel-motel taxes is to be funded by the Falcons, the NFL and proceeds from the sales of personal seat licenses.

Additional hotel-motel tax funds, under the 2010 extension of that tax the Legislature approved, must go toward financing, maintaining and operating the stadium over the next 30 years.

The stadium is set to open in 2017, but city officials haven’t yet named the site of the new stadium.

Perry reiterated that his group’s only goal is to take the issue to a vote regardless of the outcome.

“For us, the victory is the voters getting to decide,” he said. “If the majority of voters say we want the money to go to the stadium, so be it.”

But first, the nonprofit has the behemoth task of collecting thousands of verifiable signatures. Common Cause is relying on volunteers, Perry said, to launch a door-to-door grassroots campaign.