The Illinois Legislature concluded a marathon session over the weekend without advancing a bill to overhaul the state’s gun licensing program, which means that the most significant policy proposal to have emerged from February’s mass shooting in Aurora has been shelved.

The bill — which would have raised the fee for a Firearm Owner’s Identification card, funded a new State Police task force, and required fingerprinting for prospective gun buyers — passed the House by a 62-to-52 vote on May 29. But Democratic lawmakers were unable to gather enough votes in the Senate to send the bill to Governor J.B. Pritzker before the chamber adjourned June 2.

Proponents expressed disappointment in the outcome, but signaled plans to revisit the measure when the Legislature reconvenes in November. “We were one, possibly two votes short of being able to pass it, so instead of calling it and being unsuccessful we decided to hold off and see if we can align more senators over the summer,”  said the legislation’s chief sponsor, Representative Kathleen Willis, a Democrat from Northlake. “It’s not over. It’s just on hiatus.”

Willis introduced the legislation after State Police officials admitted having erroneously granted a FOID card to the Aurora gunman in 2014 because a background check based on his name and birthdate missed a prior felony conviction in Mississippi, where he had served prison time for stabbing a former girlfriend and beating her with a baseball bat.

The police realized their mistake after the gunman requested a concealed carry permit and volunteered his fingerprints to expedite the application. The fingerprints turned up his felony record, prompting the police to revoke his FOID card. But by that time, he had already used the license to purchase a Smith & Wesson pistol, and police never followed up to retrieve the gun, a lapse that has been blamed on ambiguities in the law and a lack of resources for law enforcement. In February, the gunman used that pistol to stalk his co-workers at the Henry Pratt Company manufacturing facility in Aurora, killing five people and injuring several police officers before dying in a shootout with authorities.

A subsequent investigation conducted by The Trace and co-published with The Chicago Sun-Times found that the federal criminal history database used to conduct background checks on prospective gun buyers across the country is vulnerable to significant numbers of errors when fingerprints are excluded from the search. The investigation rejuvenated efforts to pass a fingerprinting requirement in Illinois, where many believe that the Aurora gunman would have been prevented from obtaining his weapon if fingerprints were part of the FOID application process.

Willis’s initial legislation drew pushback from fellow House Democrats worried about the impact of raising the fee for a FOID card from $10 to $50 while simultaneously requiring first-time applicants to pay for fingerprint collection and the background check, which could have pushed the total cost of a gun license well above $100. To assuage her colleagues, Willis proposed reducing the fee increase to $20 and capping the amount that fingerprint collection vendors could charge. A slice of the fee increase would have funded a State Police task force charged with investigating revoked FOID card holders who failed to surrender their firearms. The bill also would require FOID-holders to undergo background checks when purchasing guns in private transactions.

As the close of the legislative session drew near, senators remained concerned about the costs to low-income FOID card applicants and felt skittish about the fingerprinting requirement, and instead of focusing on the gun licensing revamp, they turned to passing several other major proposals, including the legalization of recreational marijuana and a $40 billion spending plan for the next fiscal year.

“We just didn’t have enough time,” said Kathleen Sances, president of the Illinois Gun Violence Prevention Political Action Committee, which helped write Willis’s legislation. “But we think this bill will go a long way in keeping Illinoisians safer, and we’re going to stay on it.”