The U.S. Senate’s consideration of new firearm regulations took a legal turn on Tuesday, with conflicting testimony about whether the U.S. Supreme Court’s recent Second Amendment rulings prohibit Congress from adopting measures to reduce gun violence.

"My answer to that is an emphatic ‘no,’ " said constitutional scholar Laurence Tribe, who has argued before the Supreme Court 35 times. Tribe, a Harvard Law School professor, told a Senate subcommittee that he reviewed of the District of Columbia v. Heller ruling from 2008 and McDonald v. Chicago from 2010.

"That pair of decisions demolishes the slippery-slope theory of those who oppose basically all firearms regulation on the view that once we permit any new firearms regulation at all, we will be inviting the government, step-by-step, to come ever closer to disarming the people," Tribe testified.

Tribe said the rulings took off the table options including an outright ban of all firearms, but left open regulatory tools like those now before the Senate. They include regulating the sale and transfer of guns; bans on high capacity magazines and weapons outfitted for them; bans on straw purchasers; universal background checks; or federal gun registration.

Sitting on the other end of the table was Charles Cooper of Cooper & Kirk in Washington, a longtime National Rifle Association litigator, who said that those two Supreme Court precedents protect weapons commonly used for lawful purposes including self-defense, including those bearing high-capacity magazines.

"The amendment is one of the few enumerated constitutional provisions that specifically protects the possession and use of a particular piece of property—arms," Cooper testified. "Standard magazines holding more than 10 rounds, and the firearms outfitted for them, are by any reasonable measure in quite common use in the United States."

The testimony gave a brief glimpse into the court arguments likely to follow passage of a bill at the center of the hearing, the Assault Weapons Ban of 2013 proposed by Senator Dianne Feinstein (D-Calif.). Her bill would ban certain semiautomatic weapons and large-capacity weapons, according to a Congressional summary of the bill.

Todd Ruger is a reporter for The National Law Journal, a Legal affiliate based in New York.