Attorney General William Barr determined in his summary on Sunday that President Donald Trump did not obstruct justice in the FBI's Russia investigation.

Barr's conclusion came after the special counsel Robert Mueller conducted a "thorough factual investigation" into the question but "did not draw a conclusion — one way or the other — as to whether the examined conduct constituted obstruction."

According to Barr's summary of Mueller's final report, the special counsel has not concluded that the President committed a crime, but the report also "does not exonerate him.'"

Barr and Deputy Attorney General Rod Rosenstein concluded that Trump did not obstruct justice because Mueller did not find evidence that Trump was guilty of an underlying crime directly connected to Russia's election interference. Because of that, Barr wrote, it would be difficult to prove beyond a reasonable doubt that Trump had corrupt intent.

Democratic lawmakers and Justice Department veterans seized on Barr's conclusion, arguing that because he wrote a memo saying the obstruction probe was "legally unsupportable," he was not objective in making his determinations.

Attorney General William Barr concluded that President Donald Trump did not obstruct justice in the special counsel Robert Mueller's Russia investigation, according to a summary that Barr released to Congress on Sunday.

According to Barr's summary, Mueller found that Russia's interference in the 2016 election had two key prongs: a social-media disinformation operation, and a hacking operation aimed at stealing and disseminating damaging material during the election. The special counsel did not find any evidence of conspiracy or coordination between the Trump campaign and the Russians, Barr's letter said.

With respect to obstruction, Barr wrote that Mueller conducted a "thorough factual investigation" into the question and "ultimately determined not to make a traditional prosecutorial judgment" and "did not draw a conclusion — one way or the other — as to whether the examined conduct constituted obstruction."

Read more: Barr's summary of the Mueller report is out. Here are the key Trump-Russia questions we still don't have answers to.

Mueller's focus on the obstruction question has been well reported in the media. According to a list of nearly 50 questions the special counsel sent to Trump last year that The New York Times reported on, Mueller expressed particular interest in:

Trump's decision to fire FBI director James Comey.

Whether Trump knew about former national security adviser Michael Flynn's conversations with then Russian ambassador Sergey Kislyak about US sanctions, and why Trump went so far to protect Flynn after he was forced to resign.

Trump's role in allegedly dictating an initially misleading statement that his son, Donald Trump Jr., put out after The Times revealed the existence of a June 2016 Trump Tower meeting with Russian lobbyists.

Trump's anger at then Attorney General Jeff Sessions for recusing himself from the Russia investigation.

Trump's reported efforts to have Mueller removed as special counsel.

President Donald Trump talks with reporters before boarding Marine One on the South Lawn of the White House, Friday, March 22, 2019, in Washington. (AP Photo/Evan Vucci) Associated Press

Read more: Mueller found that there was no Trump-Russia conspiracy but did not 'exonerate' the president on obstruction

According to Barr's summary, for each of Trump's actions that Mueller investigated, his report "sets out evidence on both sides of the question" but did not resolve what Mueller characterized as "difficult issues" regarding whether Trump's actions — and intent — could amount to obstruction.

Critically, Barr wrote: "The Special Counsel states that 'while this report does not conclude that the President committed a crime, it also does not exonerate him.'"

Barr wrote that he and Deputy Attorney General determined, after consulting with officials at the Justice Department, including those in the Office of Legal Counsel, that the evidence Mueller laid out was not sufficient enough to prove beyond a reasonable doubt that Trump committed an obstruction crime. Barr emphasized that he and Rosenstein made that determination independent of department policy that states that a sitting president cannot be indicted.

Attorney General William Barr AP Photo/Carolyn Kaster

Barr also laid out how he and Rosenstein came to their determination. They noted that in order to prove obstruction, prosecutors have to establish that a defendant had corrupt intent. But Barr wrote that because Mueller did not find evidence that Trump was involved in "an underlying crime related to Russian election interference," he likely did not have corrupt intent.

"In cataloging the President’s actions, many of which took place in public view, the [Mueller report] identifies no actions that, in our judgment, constitute obstructive conduct, had a nexus to a pending or contemplated proceeding, and were done with corrupt intent, each of which, under the Department’s principles of federal prosecution guiding charging decisions, would need to be proven beyond a reasonable doubt to establish an obstruction-of-justice offense," Barr's letter said.

Read more: The House Judiciary Committee will call Attorney General William Barr to testify about the Mueller report

Democrats accuse Barr of bias

Democratic lawmakers immediately seized on Barr's determination, saying that he is inherently biased because of a memo he wrote last year in which he called Mueller's obstruction investigation "legally insupportable" and said it should not be sanctioned by the Justice Department.

Barr sent the memo to the White House, Trump's legal team, the Justice Department, and lawyers representing several others in the Russia probe.

Rep. Jerry Nadler, the chairman of the House Judiciary Committee, called out "very concerning discrepancies" in Barr's summary and said Barr will be called to in testify before the House Judiciary Committee "in the near future."

House Speaker Nancy Pelosi and Senate Majority Leader Chuck Schumer shared similar views on Barr's conclusions, and released a statement accusing Barr of bias.

"Given Mr. Barr’s public record of bias against the Special Counsel’s inquiry, he is not a neutral observer and is not in a position to make objective determinations about the report," they said in a joint statement.

Democratic Sen. Richard Blumenthal said in a tweet, "On obstruction of justice, the Special Counsel tossed a jump ball, & the AG tipped it to President Trump, but shared none of the information supporting his conclusion."

Justice Department veterans also expressed doubts about Barr's legal determination.

"Because of [Barr's] exposed memo, it will be difficult for people to have confidence, especially here where he stepped in to make a decision Mueller declined to make on obstruction," former federal prosecutor Joyce Vance tweeted.

One former senior Justice Department official who worked closely with Mueller when he was FBI director told Business Insider it was "absurd" that Barr determined Trump did not obstruct justice, saying it was "impossible" for him to determine Trump did not have corrupt intent because Trump never sat down for an interview with the special counsel.