WASHINGTON  Judge Sonia Sotomayor, President Obama’s Supreme Court choice, has a blunt and even testy side, and it was on display in December during an argument before the federal appeals court in New York. The case concerned a Canadian man who said American officials had sent him to Syria to be tortured, and Judge Sotomayor peppered a government lawyer with skeptical questions.

“So the minute the executive raises the specter of foreign policy, national security,” Judge Sotomayor asked the lawyer, Jonathan F. Cohn, “it is the government’s position that that is a license to torture anyone?”

Mr. Cohn managed to get out two and a half words: “No, your hon .”

Judge Sotomayor cut him off, then hit him with two more questions and a flat declaration of what she said was his position. The lawyer managed to say she was wrong, but could not clarify the point until the chief judge, Dennis G. Jacobs, stepped in, asking, “Why don’t we just get the position?”

To supporters, Judge Sotomayor’s vigorous questioning of the Bush administration’s position in the case of the Canadian, Maher Arar, showcases some of her strengths. She is known as a formidably intelligent judge with a prodigious memory who meticulously prepares for oral arguments and is not shy about grilling the lawyers who appear before her to ensure that she fully understands their arguments.