Weapons possession convictions are a dime a dozen at the Markham Courthouse. Javon "Big Lord" Patterson's was a notable exception.

He is Markham's first "armed habitual criminal."

The Calumet City man, who received eight years for his offense, was the first sentenced in Markham under a 2005 Illinois statute imposing stiffer mandatory minimum sentences for gun offenders with two prior forcible felony convictions.

Under the "armed habitual criminal" act, anyone who "receives, sells, possesses or transports" a gun earns Class X offender status. Their punishment: a six-to-30 year prison sentence.

More than half of the country has adopted some sort of "three strikes" legislation. The merits of these laws have been hotly debated nationwide.

Proponents say the stricter sentencing guidelines keep dangerous criminals off the streets. Detractors call them overly harsh and far-reaching.

"These mandatory laws cast a broad net," said Marc Mauer, executive director of The Sentencing Project, a Washington, D.C.-based group that advocates sentencing reform. He argued that three strikes laws are ineffectual and unfair.

Patterson, 26, was arrested in April outside his parents' home in Harvey for unlawful weapons possession. With prior convictions for armed robbery in 1997 and gun possession in 2003, the father of three qualified for the new designation of "armed habitual criminal." Under the terms of the law, Patterson must serve 85 percent of his sentence.

Dan Maloney, the Cook County assistant state's attorney who prosecuted Patterson's case, said the penalty was appropriate.

"It's not someone being caught with a one-time mistake. It's someone who's been convicted of two prior offenses," Maloney said. "And now they've been caught with a gun and deserve to spend significant time in jail. The line's been drawn."

Before the law was introduced, repeat gun offenders faced three- to-14 year prison sentences and rarely served more than seven, Maloney said.

"It has really set a new tone for habitual criminals," he said.

State Rep. James Brosnahan, D-Oak Lawn, who introduced the bill, said he modeled it after a federal program, Project Safe Neighborhoods, that had been successful in curbing gang violence nationwide.

"We were trying to make penalties for firearms more commensurate with federal penalties," Brosnahan said, adding that stiffer penalties were at the heart of Project Safe Neighborhoods' success.

Brosnahan said that, like other three-strike laws, the intention of the Illinois bill was to create disincentives for criminals.

Mauer rejected the notion.

"There is virtually no research evidence that suggests (it has) had a deterrent effect," he said.

Beyond Patterson, Maloney said he has roughly 10 armed habitual criminal cases pending.