Convicted sex offender James Nichols said he was trying to better himself by going to church. But the police who arrested him explained: The church is off-limits because it has a daycare center.

Now Nichols is challenging North Carolina's sex-offender laws in a case that pits the constitutional right to religious freedom against the state's goal of protecting the public from child molesters.

"I just started asking the question, 'Why? Why am I being treated this way after trying to better myself?'" said Nichols, a 31-year-old who was twice convicted of indecent liberties with a teen girl and again in 2003 for attempted second-degree rape. "The law gives you no room to better yourself."