The head of the House Oversight committee muted one of his invited witnesses on Wednesday for testifying in favor of tougher gun laws.

Rep. Darrell Issa (R-Calif.) said an ATF official's promotion of gun reform fell "outside the scope" of the hearing and "would not be considered valid testimony."

Appearing before the panel, Peter Forcelli, a special agent for the Bureau of Alcohol, Tobacco, Firearms and Explosives (ATF), told lawmakers that straw purchasers – those who buy guns on behalf of others – should be hit with stiffer penalties to discourage gun trafficking.


"I think perhaps a mandatory minimum one-year sentence might deter an individual from buying a gun," Forcelli said.

He was responding to a question from Rep. Carolyn Maloney (D-N.Y.), who said the current penalties are so weak that they discourage state prosecutors from pursuing straw-purchase cases. Forcelli agreed the current penalties do little to intimidate straw purchasers.

That brief exchange prompted Issa to intervene.

"We're not here to talk about proposed gun legislation," Issa said.

"I want to caution the witnesses that the scope of your testimony here is limited, and it is not about proposed legislation and the like, and under House rules would not fall within the scope of this [hearing]," Issa said. "So anecdotally you can have opinions, but ultimately it would not be considered valid testimony."

Maloney defended her line of questioning, saying she was "trying to figure out why … prosecutors often decline these gun cases."

Rep. Elijah Cummings (Md.), the senior Democrat on the oversight panel, also questioned Issa's authority to mute Forcelli.

Issa had called the hearing to examine a controversial ATF operation – dubbed "Fast and Furious" – that put firearms into the hands of known drug smugglers in order to track them to Mexican cartel leaders. 

Hundreds of those firearms have gone missing and several have been linked indirectly to the murder of border patrol agent Brian Terry, who was killed in a December firefight in Arizona. Terry's family submitted a statement to Wednesday's oversight hearing, calling for the prosecution of everyone – even government agents – involved in the tragedy.

"We ask that if a government official made a wrong decision that they admit their error and take responsibility for his or her actions," the statement read. "We hope that all individuals involved in Brian’s murder and those that played a role in putting the assault weapons in their hands are found and prosecuted to the full extent of the law."

Both parties have attacked the ATF program, but gun-reform advocates have also used the controversy to argue that ATF officials need more legal tools to track guns. 

"The wisdom of specific law enforcement operations against gun traffickers who funnel arms to Mexican drug cartels is worthy of close examination," Paul Helmke, president of the Brady Campaign to Prevent Gun Violence, said Wednesday in a statement. 

"It's also critically important that we examine why our gun laws are so weak that they make trafficking so easy in the first place." 

Backed by the gun lobby, most Republicans oppose any move to strengthen the nation's gun laws. Tougher restrictions, they argue, would erode the Second Amendment rights of law-abiding Americans.