ST. LOUIS - A St. Louis judge's decision whether to permanently block Missouri's law that would let many citizens carry concealed guns almost certainly won't be the last word.

Thirteen days since he prevented the law from taking effect Oct. 11, citing unresolved constitutional concerns, Circuit Judge Steven Ohmer on Thursday was to hear arguments over whether his injunction should be permanent.

Missouri Attorney General Jay Nixon has said the hearing's outcome would set the stage for a direct appeal - by whichever side loses - to the Missouri Supreme Court.

"You bet," Burton Newman, a St. Louis attorney for the plaintiffs, said Wednesday, expecting Ohmer to take Thursday's arguments and written briefs under advisement and rule later.

The law - enacted when the state Legislature overrode Gov. Bob Holden's veto last month - would allow Missourians at least age 23 who pay $100 and pass criminal background checks and training courses to get permits from their county sheriffs to carry concealed guns. It also would allow anyone 21 or older to conceal a gun in a vehicle without need of a permit.

Opponents sued in St. Louis on such claims that the law violated a Missouri Constitution provision dating to 1875 that guarantees the right to bear arms and adds, "but this shall not justify the wearing of concealed weapons."

Ohmer cited that clause in his initial ruling, saying it cast enough doubt on the law's constitutionality that it warranted review.

Newman also considers the conceal-and-carry measure illegal because the Legislature has not appropriated funds to cover new services required for permits to be issued, including costs of paperwork, labor and fingerprinting by sheriffs.

And Newman considers the law simply too vague - including about exactly where a gun in a vehicle can be kept - and blind to voter rejection of Proposition B, a 1999 referendum on concealed weapons.

"With that (ballot measure), the Legislature essentially said, 'We're referring this to you, Missouri's voters, because we want to know what your will is,'" Newman said. That measure narrowly was turned back because of lopsided "no" votes in St. Louis and Kansas City.

Nixon's office, which defended the law's constitutionality, has claimed that the questioned constitutional clause was a "reservation" - not an absolute prohibition on lawmakers passing concealed-guns laws, which now exist in 44 states.

In its legal brief Monday, Nixon wrote that "plaintiffs seek this unprecedented judicial intrusion armed with nothing more than a single, inapposite phrase from the Missouri Constitution. Having wholly failed to carry their burden," the lawsuit's claims "must fail," he argued.

"Missourians have enjoyed the constitutional right to bear arms for nearly two centuries, and Missouri courts have zealously protected that right," Nixon wrote.

On Wednesday, Nixon's office declined comment on the matter.

The National Rifle Association weighed in Monday, arguing in a "friend of the court" brief that the clause Ohmer cited in issuing the temporary injunction does not block the state Legislature from letting Missourians carry concealed guns.

Citing the NRA's spending $3.8 million in support of 1999's Proposition B, Newman said "the NRA doesn't have any credibility in this issue. They just want to advance their own cause - the proliferation of weapons."