The three judges in the Court of Appeals, who appeared skeptical of Trump's attorneys' sweeping claims of complete presidential immunity, will weigh the issue following today's hearing.

The judges have not indicated when a ruling is expected.

Despite the Supreme Court's refusal to take up Trump's claims of immunity last month, the issue may still end up before the Supreme Court, depending on how the appeal plays out.

Former President Trump again stressed that he is entitled to presidential immunity in remarks following his court appearance during today's hearing.

"A president has to have immunity," he told reporters. "And the other thing was, I did nothing wrong. We did nothing wrong."

"When they talk about the threat to democracy, that's your real threat to democracy," Trump said of the election interference case against him. "And I feel that as a president, you have to have immunity. Very simple. And if you don't, as an example of this case, where loss of immunity, and I did nothing wrong, absolutely nothing wrong -- I'm working for the country. And I worked very hard on voter fraud because we have to have free elections."

Trump warned that the case against him will set "a very bad precedent."

"It's a very bad thing. It's a very bad precedent," he said. "As we said, it's the opening up a Pandora's box and it's a very, that's a very sad thing that's happened with this whole situation."

-ABC News' Lalee Ibssa

In his rebuttal to the special counsel team's arguments, Trump attorney D. John Sauer responded to special counsel attorney James Pearce's statement that the country has a "frightening future" if the criminal prosecution of a president is only possible if they are both impeached and convicted first.

"The 'frightening future' that he alleges, where presidents are very, very seldom if ever prosecuted because they have to be impeached and convicted first, is the one we've lived under for the last 235 years," Sauer said. "That's not a frightening future, that's our republic."

"What he is forecasting is a situation where the floodgates will be opened. We are in a situation where we have the prosecution of the chief political opponent who is winning in every poll [in the] election upcoming next year and is being prosecuted by the administration that he's seeking to replace. That is the frightening future that is tailor-made to launch cycles of recrimination that will shake our republic for the future."

The hearing concluded after Sauer finished his rebuttal. Trump may offer some remarks about the proceedings in a little while.

Special counsel attorney James Pearce delivered a fiery response to questions about the implications of Trump's indictment, calling it an "extraordinarily frightening future" if a president were to be granted complete presidential immunity.

"I mean, what kind of world are we living in?" Pearce said. "If, as I understood my friend on the other side to say here, a president orders a SEAL team to assassinate a political rival and resigned, for example before an impeachment, it's not a criminal act. I think that is extraordinarily frightening future."

Judge Karen Henderson asked Pearce how the court could rule regarding presidential immunity in a way that "would stop the floodgates?"

"I want to push back a little bit against this idea of a floodgate." Pearce responded, arguing that Smith's indictment of Trump was not risking a continuation of "tit-for-tat" prosecutions that could cascade into the future.

"The various investigations in the Clinton era didn't result in any charges. The fact that this investigation did doesn't reflect that we are going to see a seachange of vindictive tit-for-tat prosecutions in the future. I think it reflects the fundamentally unprecedented nature of the criminal charges here," he said.

"Never before has there been allegations that a sitting president has, with private individuals and using the levers of power, sought to fundamentally subvert the democratic republic and the electoral system. And frankly, it's that kind of fact pattern arises again, I think it would be awfully scary if there weren't some sort of mechanism by which to reach that," he argued.

Donald Trump's motorcade arrived at the courthouse at 9:15 a.m. ET.

He entered the building through an underground garage and did not make remarks.