Michael Flynn is central figure in brewing political drama surrounding Comey testimony Comey is set to testify that Trump asked him to stop probe of Flynn.

 -- General Michael Flynn, the most prominent target of the FBI’s investigation of Russian election interference, is expected to emerge Thursday at the center of the brewing political firestorm over allegations that President Trump made repeated entreaties to then-FBI Director James Comey to drop his investigation.

“One of the important questions is what was the president’s intent when he allegedly said to Mr. Comey ‘Go easy on Flynn,’” Senator Angus King, an independent from Maine, told ABC News.

Comey is set to testify that President Trump made repeated requests to the director to drop the investigation of Flynn, according to the advance copy of Comey’s upcoming testimony before the Senate Intelligence Committee on Thursday.

It remains unclear, King said, whether those alleged requests were motivated by compassion for Flynn, loyalty to the man who strongly backed his candidacy, or driven by self-preservation aimed at keeping Flynn from being forced to share more about any questionable relationship between the Trump campaign and the Russian government.

The probe, which has already ensnared several current and former associates of President Donald Trump, has expanded to look at a questionable paid appearance Flynn made in Russia and side work Flynn was doing in the midst of the 2016 campaign through his consulting firm, the Flynn Intel Group.

The firm belatedly filed papers with the Justice Department to disclose work he did that could have benefitted the Turkish government. Flynn also accepted $45,000 to attend a dinner in Moscow with Russian President Vladimir Putin and his firm received $500,000 from a Dutch company with ties to Turkey.

Flynn first came under investigation for his ties to Russia during the campaign when he was Donald Trump’s senior foreign policy adviser and a strident supporter.

After the election, during the transition, Flynn failed to report that he had secretly met with the Russian ambassador, even lying to vice-president elect Michael Pence about discussing lifting sanctions with the ambassador at that meeting. Pence then unknowingly repeated the lie to the public.

That discussion was at the heart of President Trump’s request to the then-FBI director to drop the investigation, according to the advance copy of Comey’s testimony.

“I hope you can see your way clear to letting this go,” Comey says Trump told him. Comey said he gave the president no such assurances before he was suddenly fired in May.

In March, Flynn's lawyer, Robert Kelner, defended his client from the swirl of allegations that have dogged him since Trump was elected.

"Gen. Flynn is a highly decorated 33-year veteran of the U.S. Army," Kelner said. "He devoted most of his life to serving his country, spending many years away from his family fighting this nation’s battles around the world ... Notwithstanding his life of national service, the media are awash with unfounded allegations, outrageous claims of treason, and vicious innuendo directed against him."

It’s not just Flynn’s behavior that will face intense scrutiny during Comey’s testimony. According to Matt Olsen, a former federal prosecutor for the FBI and an ABC News contributor, Trump’s alleged attempts to pressure Comey have landed him in the spotlight as well.

“It appears that the president is really trying to isolate the investigation, really establish a firewall around the White House by asking Comey to drop the investigation,” Olsen told ABC News. “Again, something that's completely inconsistent with the principle of the rule of law.”

According to John Carlin, the former assistant attorney general for national security at the Department of Justice who is now an ABC News contributor, if it appears that Trump’s actions rose to the level of obstruction of justice, lawmakers could be heading into uncharted territory.

“The key here isn't whether it violates a criminal statute because you can't bring that criminal charge against a sitting president,” Carlin told ABC News. “So I think at the end of the day you have to look as to whether this is an impeachable offense. And there's not a lot of precedent there.”