According to a source familiar with the matter, former Vice President Mike Pence testified Thursday before a federal grand jury investigating efforts by then-President Donald Trump and his allies to overturn the results of the 2020 presidential election.

Pence's appearance before a grand jury in Washington, D.C., investigating the president he once devotedly served is a landmark in the Justice Department's investigation and will likely provide prosecutors with a crucial first-person account of certain conversations and events in the weeks preceding the deadly uprising on January 6, 2021, according to WTOP.

It also has significant political ramifications, given that Pence has hinted at running for president in 2024 against Trump, the Republican frontrunner.

The Testimony

The testimony, which was verified by someone familiar with the matter who insisted on anonymity to discuss a secret grand jury matter, took place hours after a federal appeals court denied Trump's attorneys' request to prevent Pence's appearance.

Earlier this year, Pence was subpoenaed to testify, but Trump's attorneys objected, citing executive privilege concerns. In March, a judge refused to block Pence's appearance but sided with the former vice president's constitutional arguments that he could not be compelled to answer questions related to his role as the Senate's presiding officer over the certification of ballots on January 6.

“We’ll obey the law, we’ll tell the truth,” Pence said in an interview with CBS News’ “Face the Nation” that aired Sunday. “And the story that I’ve been telling the American people all across the country, the story that I wrote in the pages of my memoir, that’ll be the story I tell in that setting.”

It was not immediately obvious what Vice President Pence may have told the grand jury, but he was the most prominent member of the Trump administration to be summoned to testify. Within the federal facility where the grand jury has been convening, just blocks from the U.S. Capitol, security was heightened due to the presence of Vice President Pence, with an unusual amount of activity from U.S. Marshals.

What Happened Prior

In the days preceding up to January 6, Pence spoke extensively about Trump's pressure campaign imploring him to reject Democrat Joe Biden's presidential election victory, including in his book "So Help Me God." Pence, as vice president, had a ceremonial role overseeing Congress's tallying of the Electoral College vote but lacked the ability to influence the results, despite Trump's assertions to the contrary.

Pence, a former Indiana governor and congressman, has stated that Trump put his family and everyone else at the Capitol that day in peril, and that history will hold him "accountable."

“For four years, we had a close working relationship. It did not end well,” Pence wrote, summing up their time in the White House.

Trump was delivering a speech in New Hampshire when the news of Pence's grand jury appearance leaked. Trump replied at a restaurant when asked if he was apprehensive about his testimony, "No, I'm not, and I don't know anything about it."

Pence's attorneys raised their own, more limited objection to the subpoena. They argued that because Pence was serving as president of the Senate on January 6 while electoral votes were being counted in Congress, he was protected from being compelled to testify about that process by the Constitution's "speech or debate" clause, which is designed to shield members of Congress from being questioned about official legislative acts.

A judge concurred with the argument, effectively limiting the scope of the witness's anticipated testimony.

Jack Smith, the special counsel for the Justice Department overseeing the investigation, has sought the testimony of a lengthy list of former Trump aides, including former White House counsel Pat Cipollone and former adviser Stephen Miller.

Separately, Smith is investigating the potential mishandling of hundreds of classified documents at Trump's estate in Palm Beach, Florida, Mar-a-Lago, as well as any attempts to obstruct this investigation. It is unclear when either investigation will conclude or who, if anyone, will be charged.