It would be a daunting task for anyone making his first argument before the Supreme Court.
As the lawyer representing a group of Colorado voters seeking to block former President Donald J. Trump from the ballot, Jason Murray, 38, stood before a skeptical majority in a high-stakes argument that could shape the course of the presidential election.
He was also appearing before two of his former bosses: Justices Elena Kagan and Neil M. Gorsuch.
After finishing Harvard Law School, he clerked for Justice Gorsuch, then a judge on the U.S. Court of Appeals for the 10th Circuit, and later spent a year working for Justice Kagan, finishing in 2014.
The pair are often on opposing sides in ideologically charged cases on issues like abortion, voting rights and affirmative action. But both Justice Kagan, a liberal nominated by President Barack Obama, and Justice Gorsuch, a Trump appointee who has helped shift the court to the right, seemed troubled by the implications of the Colorado Supreme Court’s decision to bar Mr. Trump from the primary ballot. Each pummeled Mr. Murray with a punishing barrage of questions.
Justice Kagan pushed Mr. Murray on the implications of allowing Colorado to ban Mr. Trump, questioning what would happen if the state at the heart of the case were instead a swing state like Michigan or Wisconsin.
“Maybe put most boldly, I think that the question you have to confront is why a single state should decide who gets to be president of the United States,” Justice Kagan said. “That seems quite extraordinary, doesn’t it?”
Mr. Murray responded that it was “not unusual that questions of national importance come up through different states.”
That answer did not seem to satisfy Justice Gorsuch, who chimed in.
“Do you agree that the state’s powers here over its ballot for federal officer election have to come from some constitutional authority?” Justice Gorsuch asked.
Mr. Murray tried to deflect: “Members of this court have disagreed about that.”
“I’m asking you,” Justice Gorsuch pointedly shot back, to laughter.
The exchange continued for nearly five minutes.
Justice Samuel A. Alito Jr., known for asking probing hypotheticals, pressed Mr. Murray about a situation in which a president had engaged in an insurrection but remained in office.
“During that interim period, would it be lawful for military commanders and other officers to disobey orders of the president in question?” Justice Alito asked.
When Mr. Murray telegraphed uncertainty, Justice Gorsuch immediately interjected.
“Why — why — why — why not? You say he’s disqualified from the moment it happens,” Justice Gorsuch said. “But if he is, in fact, disqualified, from that moment, why would anybody have to obey a direction from him?”
After Mr. Murray insisted it was not that straightforward and tried to advance his argument, Justice Gorsuch sounded a note of exasperation.
“Put that aside,” Justice Gorsuch demanded. He continued, “I think Justice Alito is asking a very different question and a more pointed one and a more difficult one for you, I understand, but I think it deserves an answer.”
What followed was a sharp exchange, even by the standards of the normally pointed, rapid-fire arguments.
Mr. Murray tried to shift the hypothetical to suggest what might happen if, rather than participating in an insurrection, the president had violated another term of holding office, like being under the age of 35.
The justice interrupted, “Please don’t change the hypothetical, OK?”
“I’m —” Mr. Murray tried to speak.
“Please don’t change the hypothetical. I know. I like doing it, too, but please don’t do it, OK?” the justice chided. That time, the audience didn’t laugh.