WASHINGTON — Breaking a decade-long silence, Justice Clarence Thomas on Monday suddenly started asking questions from the Supreme Court bench.

After saying nothing for years during oral arguments that have helped shape the fabric of American law, Justice Thomas seemed eager to re-engage as he subjected a government lawyer to a number of pointed inquiries. But Justice Thomas said nothing to clear up why he had chosen to end his silence now, exactly 10 years and one week after his last question.

His record will stand for a long time — it has no modern competition. It has been at least 45 years since any other member of the court went even a single term without asking a question.

Justice Thomas’s explanations for his disengagement have varied, but he has said lately that the other justices simply asked so many questions that they were rude to the lawyers before them. The member of the court who asked the most questions was Justice Antonin Scalia, whose empty seat next to Justice Thomas’s remained draped in black.