WASHINGTON (Reuters) - Clarence Thomas ended a decade of silence from the bench during Supreme Court arguments on Monday when the conservative justice unexpectedly posed questions during a gun rights case from Maine.

His comments, which surprised courtroom observers and then held them rapt, focused on Thomas’ concern that people convicted of domestic-violence misdemeanors could permanently lose the right to own a firearm. Thomas has been a consistent vote on the court for robust gun rights under the U.S. Constitution’s Second Amendment.

Thomas, 67, had not asked a question during oral arguments since Feb. 22, 2006, when he made queries during a South Carolina death penalty case.

His words came just over two weeks after the death of fellow conservative Antonin Scalia, who had been one of the most outspoken justices during arguments as well as a strong advocate for gun rights.

Thomas’ questions were directed at Ilana Eisenstein, an assistant U.S. solicitor general who was defending a federal firearms statute. At issue was when a prior state misdemeanor domestic assault conviction based on “recklessness” may lead to a person being barred from ever owning a gun again under federal law.

His first words were, “Ms. Eisenstein, one question.”

“Can you give me another area where a misdemeanor violation suspends a constitutional right?” Thomas asked.

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Eisenstein stressed that Congress was concerned about future harm by individuals convicted “of battering their family members.” She said lawmakers particularly wanted to prevent gun violence.

Thomas asked whether either of the defendants involved in Monday’s cases had used a weapon against a family member. Eisenstein said no.

“So ... the suspension is not directly related to the use of the weapon,” Thomas said. “It’s just a family member’s involved in a misdemeanor violation; therefore a constitutional right is suspended.”

Thomas, the court’s only black justice, in the past has attributed his reluctance to ask questions to a few factors, some personal.

He told a group of students in 2000 that his reluctance to speak during arguments arose from a shyness tracing to his birth in Pin Point, Georgia, and his childhood with his grandparents in nearby Savannah: “I had grown up speaking a kind of dialect.”

In part to avoid the ridicule of classmates, Thomas said, “I just started developing the habit of listening. ... I didn’t ask questions in college or law school. I could learn better just listening.”

Thomas has also said he thinks his colleagues interrupt the lawyers too much and that the lawyers should be able to explain their positions.