A redacted version of special counsel Robert Mueller's report on Russian election meddling is expected to be released to the public Thursday after a nearly two-year investigation that concluded when the findings were submitted March 22 to the Justice Department. But the fight over the probe isn't likely to end there. President Donald Trump has continued to rail on the investigation as a "witch hunt," despite claiming that the report had exonerated him. House Democrats recently launched a sweeping corruption probe involving dozens of Trump's associates, and Democrats are gearing up for a fight with Attorney General William Barr over the report's release. The Justice Department announced on the eve of the report's expected release that Barr will hold a news conference at 9:30 a.m. ET Thursday. He will be accompanied by Deputy Attorney General Rod Rosenstein. Here is a look at how the battle over the Mueller probe got to this point – and what comes next.

How we got here

The nearly 400-page report is the product of a secretive probe that included 19 lawyers and 40 investigators who interviewed hundreds of witnesses, executed nearly 500 search warrants and issued 2,800 subpoenas. All told, criminal charges were lodged against 35 people and entities, including former Trump campaign chairman Paul Manafort, the president's former personal lawyer Michael Cohen and former national security advisor Michael Flynn. The investigation into Russia's influence on the 2016 campaign has been a political lightning rod since its inception. The steady stream of bombshell reporting about the probe and its offshoots have given rise to a cottage industry of books, podcasts, entertainment and even merchandise often centered around Mueller himself. It has remained on the front burner of American politics thanks in no small part to Trump, who quickly assumed the role as the probe's critic-in-chief. The president has alleged, often on Twitter, that the probe was at best a politically motivated "witch hunt" to damage his presidency, and at worst a "deep-state" conspiracy led by Mueller and his "band of Angry Democrats" to try and remove Trump from office. The White House had no comment in advance of the report's expected release.

Special Counsel Robert Mueller departs St. John's Episcopal Church, across from the White House, after attending morning services, in Washington, Sunday, March 24, 2019. Cliff Owen | AP

All the while, Trump himself was being investigated by Mueller's team for possibly obstructing justice. Trump had fired former FBI Director James Comey in May 2017, a move that sent shockwaves through Washington and raised the question of whether the president had attempted to block or interfere with an investigation that involved his own presidential campaign. Later that month, Rosenstein appointed Mueller to investigate Russia's election meddling as special counsel, along with "any matters that arose or may arise directly from that investigation."

The FBI counterintelligence investigation into figures in Trump's orbit had been underway before the November 2016 election, in which Trump defeated his Democratic rival, former Secretary of State Hillary Clinton. Comey, who oversaw the FBI investigation before his firing and Mueller's appointment, testified before Congress behind closed doors in December that that probe originated with four Americans related to Trump during the election who were connected in some way "to the Russian interference effort." The underlying basis for the FBI's action, Comey testified, was a tip about claims made by George Papadopoulos, a foreign policy advisor who joined Trump's campaign in March 2016. Papadopoulos, 31, had met in London with professor Joseph Mifsud, who had ties to Russia. In late April 2016, Mifsud told Papadopoulos that Russians had "dirt" on Clinton, including "thousands of emails," according to the special counsel's court filings. A month later, The New York Times reported, Papadopoulos shared the details of that meeting with Australian diplomat Alexander Downer. The diplomat's tip to the FBI about Papadopoulos' remarks sparked the FBI's Trump-Russia probe, the Times reported. Papadopoulos served 12 days in prison after pleading guilty to charges lodged by Mueller. His lawyers have asked Trump for a pardon.

Barr's letter

Democrats and Republicans alike have clamored to see the final conclusions from the highly guarded investigation. But like the probe itself, the process of preparing the report for its public rollout has been the subject of intense scrutiny and controversy on Capitol Hill. Less than two days after receiving the lengthy report, Barr summarized what he said were its main conclusions in a four-page letter to congressional Judiciary Committee leaders. Barr shared two main conclusions from Mueller's probe, both of which were celebrated by Trump. The special counsel did not establish conspiracy or coordination between the Trump campaign and the Kremlin, Barr wrote, quoting an excerpt from the report itself. On the question obstruction, Barr quoted Mueller saying the report "does not conclude that the President committed a crime, [but] it also does not exonerate him." Mueller's lack of a definitive stance on obstruction left the final decision to Barr and Rosenstein. They concluded: "The evidence developed during the special counsel's investigation is not sufficient to establish that the president committed an obstruction of justice offense." Both sides of the political aisle were quick to respond that evening. "No Collusion, No Obstruction, Complete and Total EXONERATION," Trump tweeted, even though he was not exonerated by Mueller. Trump TWEET House Speaker Nancy Pelosi, D-Calif., and Senate Minority Leader Chuck Schumer, D-N.Y., immediately went after Barr's credibility, saying in a statement that the attorney general "is not a neutral observer and is not in a position to make objective determinations about the report." Some Democrats had voiced concerns that Barr may have pre-judged the Mueller probe in light of an unsolicited memo he sent to the Justice Department last June criticizing the Mueller probe's obstruction inquiry as "fatally misconceived." In addition, reports from The New York Times and Washington Post citing several members of Mueller's team poured gasoline on the firestorm of controversy following Barr's summary. The team members, speaking on the condition of anonymity, reportedly said that the evidence that Trump tried to obstruct the probe is stronger than Barr has publicly suggested. Barr holds the ultimate authority on the report's release. He gained oversight responsibilities from Rosenstein, who himself adopted those duties after former DOJ head Jeff Sessions recused himself from any investigations into Russian election meddling. While Barr has vowed to be as transparent as possible in the handling and release of the report, he has made clear that both Congress and the public will see a version of the report that contains redactions in four areas. The attorney general said the redactions will be color-coded, so that readers can better understand why certain information was hidden. That material includes information about intelligence sources and methods, details of ongoing investigations and other information that would "unduly infringe on the personal privacy and reputational interests of peripheral third parties." But the most controversial redaction category involves the DOJ's insistence that information related to Mueller's grand jury cannot be released under federal law. Democratic lawmakers, led by House Judiciary Chairman Jerrold Nadler of New York, have pushed back on that argument, claiming Barr could share that information with Congress if he wanted to.

What to look for in the report

The special counsel delivered the report to the Justice Department on March 22, bringing the probe to its official conclusion. Still, a handful of cooperating witnesses and criminal cases lodged by the probe remain active, even as Mueller's team members have taken on other jobs. The Times reported that Mueller's team had prepared and provided several summaries of their own to Barr, which the attorney general opted not to use. "I decided that none of it was releasable the way I received it," Barr testified before a Senate Appropriations subcommittee last Wednesday. It's unclear if those summaries will be included in the release of the redacted report. The attorney general said he would give the redacted report to both Congress and the public.

One thing not to expect: any new indictments or criminal charges. "The report does not recommend any further indictments, nor did the special counsel obtain any sealed indictments that have yet to be made public," Barr wrote in his March 24 letter. Barr said the report is "nearly 400 pages" in length — but that may not include footnotes, citations, raw evidence exhibits and other information. Democrats want Barr to give them all of it. Of course, the leaders of both parties are expected to comment on the report shortly after it's made public, including the president. "I'd expect" that Trump will speak out after the report is released, White House senior advisor Kellyanne Conway said in a Fox News interview. "In those 400 pages, we know what does not exist and it's collusion," Conway added.

What's next