In December, a panel of the 7th U.S. Circuit Court of Appeals ruled that Illinois' ban on carrying concealed weapons in public was unconstitutional. "A right to bear arms thus implies a right to carry a loaded gun outside the home," Judge Richard Posner wrote in the majority opinion.

"A gun is a potential danger to more people if carried in public than just kept in the home," he wrote. "But the other side of this coin is that knowing that many law-abiding citizens are walking the streets armed may make criminals timid."

Posner directed Illinois lawmakers to fashion a law that lifts the complete ban on carrying guns in public. The judge didn't tell them how to do that, but he told them when they had to get it done. He set a deadline: 180 days.

More than half that time has passed, but lawmakers have not found much consensus on a concealed carry bill. Gun rights advocates want a broad, permissive law. Gun control advocates want, well, they don't really want any law. But faced with the order of the court, they're focused on creating a fairly restrictive law.

So what law can pass the Legislature and the scrutiny of the courts?

The U.S. Supreme Court gave a welcome signal this week. It declined to review a federal appellate court ruling that upheld the constitutionality of New York state's concealed carry law, considered one of the more restrictive in the nation.

New York is a "may-issue" state. That is, local law enforcement officials may grant concealed carry permits, but they have broad authority to deny permits to applicants who don't demonstrate that they have a special need for protection. In New York City, most applicants are denied. Business owners who want to carry a loaded weapon or hire armed security guards must furnish, among other things, tax and banking records.

So there's a template for Illinois, where public safety issues in Chicago are vastly different from, say, Shelby County.

The decision by the U.S. Supreme Court doesn't set a precedent for the nation. It doesn't guarantee that a law patterned on New York would survive a court challenge, but it certainly increases the prospects that it would.

So, let's go. Illinois could live with a concealed-carry law that recognizes local needs and interests. Gov. Pat Quinn and other Democratic leaders have signaled support for that option. The gun lobby doesn't like the New York template, but it would be interesting to watch pro-gun lawmakers defend a vote to defeat a bill that for the first time establishes concealed carry in Illinois.

The Illinois Legislature is scheduled to adjourn on May 31, nine days before the clock runs out on the appellate court's grace period. That court could stay its ruling if Illinois appeals to the U.S. Supreme Court. Attorney General Lisa Madigan is wise to delay a decision on whether to appeal until the Legislature acts or doesn't act.

Bottom line, the wisest course for the Legislature is to act: Pass a "may-issue" concealed carry law that provides local control.

Lawmakers, don't wait for an emergency to pass a concealed carry bill. Don't invite the uncertainty of allowing the 180-day window to end without a new law. It's possible the ban on concealed carry would simply be lifted, without any restrictions in place. Chicago attorney John Schmidt, a gun control supporter, argues in a Tribune op-ed Wednesday that an ultimate ruling against the Illinois ban is "almost inescapable."

The appellate court has given you a time frame — six months — to find consensus. Pass a law styled after New York's.

The Illinois House this year has voted to ban semi-automatic assault weapons, limit large capacity ammunition magazines, mandate locking devices on certain weapons and increase penalties for those who sell or transfer guns illegally.

But neither the House nor the Senate has moved a comprehensive concealed carry bill to the floor for a vote.

That leaves Illinois up against the clock: tick, tick, tick.