After about an hour of questioning, Trump's attorney concluded his presentation before the court and Department of Justice attorney Michael Dreeben, representing Smith's team, began his argument with a short opening statement followed by what is expected to be approximately an hour of facing questions.

Dreeben called Trump's immunity claim a "novel theory [that] would immunize former presidents for criminal liability for bribery, treason, sedition, murder and, here, conspiring to use fraud to overturn the results of an election and perpetuate himself in power."

"Such presidential immunity has no foundation in the Constitution," Dreeben said. "The framers knew too well the dangers of a king who could do no wrong."

-ABC News' Adam Carlson

Justice Elena Kagan and Amy Coney Barrett raised the hypothetical of a potential presidential coup with Trump's attorney, who said that under their theory of immunity, ordering a coup could be considered an official act.

John Sauer maintained that impeachment and conviction are needed before a criminal prosecution in the hypothetical case of a coup raised by the justices.

And even then, Sauer said there would have to be a criminal statute expressly referencing the president, prompting an incredulous response from Barrett, who appeared to express a concern that Suer's argument was paradoxical.

"There would have to be a statute that made a clear statement that Congress purported to regulate the president's conduct," he said.

Justice Ketanji Brown Jackson said she was worried that granting Trump's position for presidential immunity would "embolden" a president to act criminally "with abandon."

"If someone with those kinds of powers, the most powerful person in the world, with the greatest amount of authority, could go into office knowing that there would be no potential penalty for committing crimes, I'm trying to understand what the disincentive is from turning the Oval Office into, you know, the seat of criminal activity in this country. ... I worry that we would have a worse problem than the problem of the president feeling constrained to following the law while he's in office," she said.

John Sauer responded by suggesting that history has shown that this hasn't happened so far. “I respectfully disagree with that because the regime you described is the regime we operated under for 234 years," he said.

As the questioning of Trump's attorney continues, Justice Elena Kagan noted that the framers of the Constitution consciously did not put in an explicit presidential immunity clause.

"They didn't provide immunity to the president," she told lawyer John Sauer. "And you know, not so surprising, they were reacting to a monarch who claimed to be against the law. Wasn't the whole point that the president was not a monarch and the president was not supposed to be above the law?"

In response, Sauer argued that the framers did put in an immunity clause "in a sense" with the executive vesting clause and that they adopted impeachment as a "structural check," which is a major part of Trump's defense against his federal charges.

"They did discuss and consider what would be the checks on the presidency and they did not say we would have criminal prosecution," Sauer said. "Everybody cried out against that as unconstitutional."

Trump appeared confident while addressing the presidential immunity hearing during remarks Thursday morning in Manhattan.

"We have a big case today -- this judge wouldn't allow me to go, but we have a big case today at the Supreme Court on presidential immunity, a president has to have immunity," Trump said at a construction site where he met with union members, workers and supporters. "If you don't have immunity, you just have a ceremonial president," he insisted.

When asked about the justices, three of whom he named to the high court, Trump said, "They're very talented people, they're very smart, they know what they're doing."

Trump stopped by the midtown Manhattan site, where the new JPMorgan headquarters is under construction, before heading to the courthouse for his hush money trial. He denies all wrongdoing.

-ABC News' Lalee Ibssa, Soo Rin Kim and Mike Pappano