After roughly two years, special counsel Robert Mueller's much-anticipated report on Russia's meddling in the 2016 election is set to be made public, with Democrats and Republicans sparring over how much of the 400-page document should see the light of day.

The release comes a month after Mr Barr penned a letter to Congress detailing the basic findings of the report, and set off a firestorm of criticism from Democrats who claimed that America's lead law enforcement official was shielding Donald Trump after a lengthy and exhausting investigation. Still, he report's release could ultimately lay bare further truths behind the foreign nation’s efforts to impact American democracy, and those who helped along the way.

The conclusion of Mr Mueller’s probe comes amid a particularly polarising period in American politics, with the nation enraptured with the slow drip of details that have emerged from the investigation and painted an alarming portrait of a vast network of individuals connected to Donald Trump and implicated in a range of crimes.

But, it appears as though any prosecution of those crimes remains a distant possibility, after Mr Barr's letter indicating that the Justice Department found insufficient evidence of crimes by Mr Trump. He also wrote that there was no collusion between the Trump campaign and Russia — a claim that comes after repeated revelations of contacts between the campaign and officials related to the Kremlin.

Here’s how we got here.

2017

17 May 2017 — Mr Mueller is appointed to as special counsel by Deputy Attorney General Rod Rosenstein. The appointment comes just over a week after Mr Trump fires former FBI Director James Comey for, among other things, investigating his campaign’s connection to Russian meddling in the 2016 election.

Trump's inner circle: Meet the members of the US president's cabinet Show all 20 1 /20 Trump's inner circle: Meet the members of the US president's cabinet Trump's inner circle: Meet the members of the US president's cabinet Donald Trump's Cabinet Donald Trump's Cabinet is one the richest in American history, filled with billionaires, conservatives and several career politicians. AFP/Getty Trump's inner circle: Meet the members of the US president's cabinet Mike Pence US Vice President Mike Pence has defended Donald Trump throughout his presidency while walking a fine line to avoid any public involvement in major scandals. AFP/Getty Trump's inner circle: Meet the members of the US president's cabinet Mike Pompeo Secretary of State Mike Pompeo replaced Donald Trump's previous appointment to the post, Rex Tillerson, and has led talks with North Korea in establishing high-profile summits between the president and Kim Jong Un. Getty Trump's inner circle: Meet the members of the US president's cabinet Wilbur Ross Secretary of Commerce Wibur Ross raised controversy when he was accused of falsely claiming to have sold stock in a bank and violated a government ethics agreement. AFP/Getty Trump's inner circle: Meet the members of the US president's cabinet Robert Lighthizer US Trade Representative Robert Lighthizer has been a fixture in Donald Trump's ongoing trade spat with China. AFP/Getty Trump's inner circle: Meet the members of the US president's cabinet William Barr Attorney General William Barr replaced Jeff Sessions as the nation's top cop in early 2019 and has refused to commit to recusing himself from the Russia probe despite an unsolicited memo he sent to the Justice Department decrying the investigation. EPA Trump's inner circle: Meet the members of the US president's cabinet Rick Perry Energy Secretary Rick Perry has held his post throughout Donald Trump's presidency despite previously undermining the need for the agency he now leads in past public statements. Ken Shipp / United States Department of Energy Trump's inner circle: Meet the members of the US president's cabinet Betsy DeVos Education Secretary Betsy DeVos has also held her post throughout the presidency, despite major backlash to her apparent undermining of the nationwide public school system and advocacy for charter programmes. Getty Trump's inner circle: Meet the members of the US president's cabinet Steven Mnuchin Treasury Secretary Steven Mnuchin has faced numerous controversies throughout his tenure as the head of Treasury, including costing taxpayers at least a million dollars in travel expenses. AP Trump's inner circle: Meet the members of the US president's cabinet Robert Wilkie Veterans Affairs secretary Robert Wilkie was appointed after Donald Trump's White House doctor Ronny Jackson withdrew over allegations he provided prescription drugs to patients without prescriptions. AFP/Getty Trump's inner circle: Meet the members of the US president's cabinet David Bernhardt Secretary of the Interior David Bernhardt took office in January 2019 after the resignation of Ryan Zinke after previously serving as Zinke's deputy. Before taking office Bernhardt worked for many years as a solicitor for the Department of the Interior. Tami Heilemann / United States Department of the Interior Trump's inner circle: Meet the members of the US president's cabinet Elaine Chao Transportation Secretary Elaine Chao has held her post throughout the presidency and has mostly avoided controversy, despite a report claiming her office has been in frequent coordination with her husband's, Mitch McConnell. AFP/Getty Trump's inner circle: Meet the members of the US president's cabinet Kevin McAleenan Acting Secretary of Homeland Security Kevin McAleenan took over from Kirstjen Nielsen after she resigned in April 2019. He previously worked as the executive director of the executive director of the Office of Anti Terrorism in the Customs and Border Protection agency United States Customs and Border Protection Trump's inner circle: Meet the members of the US president's cabinet Ben Carson Secretary of Housing and Urban Development Ben Carson was appointed shortly after Donald Trump took office and raised controversy over an exorbitant furnishing bill for his office. Reuters Trump's inner circle: Meet the members of the US president's cabinet Gina Haspel CIA Director Gina Haspel was appointed in 2018 and faced backlash surrounding her oversight of Guantanamo Bay. Getty Trump's inner circle: Meet the members of the US president's cabinet Dan Coats Director of National Intelligence Dan Coats could be the next person to leave Donald Trump's administration over his refuting the president's claims surrounding ISIS. Reuters Trump's inner circle: Meet the members of the US president's cabinet Sonny Perdue Agriculture Secretary Sonny Perdue has been dogged by ethics questions throughout his tenure and faced controversy when emails showed the agency appeared willing to eagerly work with lobbyists under his leadership. Reuters Trump's inner circle: Meet the members of the US president's cabinet Alex Azar Health and Human Services Secretary Alex Azar is a former pharmaceutical lobbyist and former drug company executive. Getty Trump's inner circle: Meet the members of the US president's cabinet Mick Mulvaney Acting Chief of Staff and Office of Management and Budget Director Mick Mulvaney has described himself as one of the most conservative officials in the White House. EPA Trump's inner circle: Meet the members of the US president's cabinet Robert Wilkie Secretary of State for Veterans Affairs Robert Wilkie has spent his career on Capitol Hill serving in various roles in foreign affairs and defence. He holds the rank of Lieutenant Colonel in the US Air Force Reserve. Gene Russell / United States Department of Veterans Affairs

14 June 2017 — The special counsel investigation, started primarily to investigate Russian meddling in 2016, widens to include whether Mr Trump obstructed justice.

The development follows after Mr Comey testified in Congress that Mr Trump had approached him to try and get him to “let go” of an investigation into former national security adviser Michael Flynn, who lid to Vice President Mike Pence about contacts he had with Russian diplomats before the president’s inauguration.

19 July 2017 — Mr Trump warns Mr Mueller against investigation the Trump family’s financial history, saying it would be crossing a red line.

“I think that’s a violation,” Trump tells the New York Times. “Look, this is about Russia.”

26 July 2017 — Federal investigators raid the home of Paul Manafort, who was Mr Trump’s 2016 campaign manager.

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30 October 2017 — Manafort and his associate Rick Gates are charged for financial and conspiracy crimes uncovered by the special counsel’s office. At the same time, a previous guilty plea by former Trump campaign adviser George Papadopoulous is revealed, showing that he misled investigators about contacts with Russian officials.

Manafort and Gates saw charges related to their work for a pro-Russia Ukrainian political party, bringing them tens of millions of dollars that they were accused of laundering.

1 December 2017 — Flynn pleads guilty to “willfully and knowingly [making] false, fictitious and fraudulent statements and representations” to investigators about his contacts with former Russian ambassador to the US Sergey Kislyak.

He agrees to cooperate with the special counsel investigation.

Donald Trump launches furious tirade against Mueller on White House lawn as he calls Comey a 'bad cop'

2018

16 February 2018 — The special counsel’s office brings charges against 13 Russian nationals and three Russian groups for working to interfere in the 2016 election.

The allegations include charges that these individuals began a concentrated campaign in 2014 to influence the election that included stealing the identities of Americans and creating false online personas.

The efforts are tied to the Russian group the Internet Research Agency, which used social media platforms like Facebook to spread disinformation and divisive rhetoric ahead of the 2016 election.

20 February 2018 — Former lawyer Alex van der Zwaag is charged by the special counsel’s office for making “materially false, fictitious, and fraudulent statements and representations” to federal investigations about contacts he had with Gates.

'I will be shocked' Donald Trump's former lawyer predicts that there will be no Mueller report

22 February 2018 — Mr Mueller’s probe files further charges against Manafort and Gates in a 32-count superseding indictment. The charges include tax fraud, bank fraud conspiracy, and failing to file appropriate reports on foreign bank accounts.

Court documents say: “Manafort and Gates generated tens of millions of dollars in income as a result of their Ukraine work. From approximately 2006 through the present, Manafort and Gates engaged in a scheme to hide income from United States authorities, while enjoying the use of the money.”

Manafort is named in 23 of the indictments.

23 February 2018 — Gates pleads guilty on conspiracy and false statement charges, and agrees to cooperate with investigators.

3 April 2018 — The first criminal sentence is handed down in relation to the Mueller probe. Van der Zwaag is sentenced to 30 days in prison, and told to pay a $20,000 fine.

9 April 2018 — Donald Trump’s former personal lawyer, Michael Cohen, becomes the target of a federal raid on his home, office, and hotel room.

Investigators raided Cohen’s properties seeking evidence related to a criminal campaign finance violation Mr Trump and Cohen allegedly paid out near the end of the 2016 campaign to adult film actress Stormy Daniels to keep her silent about an alleged affair with the president in 2006.

Donald Trump's acting attorney general shuts down questions on Mueller probe: 'Your five minutes is up'

8 June 2018 — Manafort’s longtime aide Konstantin Kilimnik is the target of new charges. He is accused of witness tampering.

13 July 2018 — Mr Mueller’s team indicts 12 Russians in relation to the 2016 hack of the Democratic National Committee’s email servers.

The 12 Russians are all members of Russian intelligence services. Former Trump adviser Roger Stone appears to be referenced in the charges, but is not named.

21 August 2018 — Manafort is found guilty on eight charges of bank and tax fraud in federal court in Virginia. Meanwhile, Cohen pleads guilty in federal court on financial crimes.

Cohen also pleads guilty to charges that have shaped up to be a major potential liability: The payments to Daniels, which totalled $130,000, to keep her silent about the alleged affair. That level of undisclosed help for a presidential campaign violates campaign finance rules, and Cohen indicates the payments were made at the discretion of “a candidate for federal office.”

7 September 2018 — Papadopoulos is sentenced to 14 days in prison.

14 September 2018 — Manafort pleads guilty to charges filed in federal court in Washington, DC. He agrees to cooperate with investigators.

26 October 2018 — Mr Mueller’s team interviews former Trump strategist Steve Bannon about Mr Stone, who had made comments suggesting he knew about the DNC email hacks before they were made public by WikiLeaks.

7 November 2018 — After Attorney General Jeff Sessions resigns, Matthew Whittaker is appointed as acting attorney general and prepares to take over oversight of the Mueller probe. Mr Whittaker faces questions about conflict of interest related to the probe for past critical remarks of Mr Mueller’s investigation.

20 November 2018 — Mr Trump reportedly submits answers to written questions from Mr Mueller’s team.

Ivanka Trump says she has 'zero concern' over Mueller investigation

29 November 2018 — Cohen admits that he lied to Congress about talks to build a Trump branded real estate project in Moscow during the 2016 campaign.

4 December 2018 — Mr Mueller recommends no jail for Flynn, touting his assistance with the Russia investigation.

7 December 2018 — New York prosecutors — in a case separate form Mr Mueller’s probe but arising from its evidence — recommend substantial prison time for Cohen, saying that even though he is cooperating with the Russia probe his crimes were substantial.

Mr Mueller writes a separate memo related to the case, saying that he is not taking a position on Cohen’s sentencing.

Elsewhere, prosecutors file charges against Manafort for allegedly lying to them and breaching his plea agreement.

12 December 2018 — Cohen receives a three year prison sentence. He is told to voluntarily surrender in March, and to pay $1.4 million in restitution, forfeit $500,000 and pay a $50,000 fine.

20 December 2018 — The House Intelligence Committee votes to turn over transcripts from its interview with Roger Stone on Russian interference from earlier in the year. Mr Stone responds that the transcripts should be made public.

Donald Trump refuses to say if he'll make Mueller report public

Donald Trump refuses to say if he'll make Mueller report public

2019

25 January 2019 — Mr Stone is arrested at his home in Florida, and faces federal charges.

15 February 2019 — Mr Mueller’s team recommends 19.5 to 24.5 years in prison for Manafort’s crimes.

22 February 2019 — The judge overseeing Mr Stone’s case issues a full gag order after he posts a photo on social media that includes the judge’s photo and a crosshair symbol.

23 February 2019 — Mr Mueller’s team files a sentencing memo for Manafort, calling him a “hardened“ criminal who “brazenly” broke the law for decades before he was caught.

7 February 2019 — Manafort is sentenced to just under four years in prison for his crimes prosecuted in Virginia, far less than the recommendation Mr Mueller submitted.

14 March 2019 — Manafort receives an additional 43 months on his sentence for his crimes charged in Washington, bring his total prison time to 7.5 years.

22 March 2019 — Mueller report sent to the attorney general's office.

24 March 2019 — Mr Barr submits a 4-page summary of the Mueller report to Congress, saying that there was no collusion and that Mr Trump will not be charged with obstruction of justice.

27 March 2019 — Mr Barr agrees to testify before Congress about the Mueller report "reasonably soon".

3 April 2019 — The House Judiciary Committee, controlled by Democrats, votes to grant chairman Jerry Nadler the power to subpoena the full and un-redacted Mueller report, and instructs Mr Barr to testify before the committee before May 2, which he had planned.

7 April 2019 — Mr Trump says he has not read the Mueller report, and calls it a "total waste of time".