Key points: Robert Mueller’s report into Donald Trump's 2016 campaign
US special counsel Robert Mueller has spent 22 months examining whether Donald Trump’s presidential campaign conspired with Russia to sway the 2016 election.
Mueller's investigation found that there was no collusion.
However, the question of whether Mr Trump obstructed justice was not so clear-cut.
In laying out Mr Mueller’s findings, US attorney general William Barr said the special counsel did not weigh in on the question.
Instead, Mr Barr ultimately made the call that Mr Trump did not violate the law - a move that drew criticism from Democrats who say the president is hardly in the clear.
Here are the key points from Mr Mueller’s findings:
No collusion between the Trump campaign and Russia
Mr Barr quoted Mr Mueller’s confidential report as saying the investigation "did not establish that members of the Trump campaign conspired or coordinated with the Russian government in its election interference activities".
This finding marks a victory for the US president, who has turned "no collusion" into a daily refrain on social media.
However, the letter is short on detail.
Mr Barr said he will have to consult with Mr Mueller and other US justice department officials before he can release more of Mr Mueller’s confidential report or any other information he gathered during the investigation.
Mr Barr’s letter did not say what Mr Mueller learned that fell short of a crime about a broad range of Trump associates who had Russia-related contacts.
It also did not answer why several of those people lied to federal investigators or US congress during the Russia probe since there was not any direct coordination going on.
No smoking gun on obstruction of justice, but no exoneration either
Mr Mueller decided not to make a judgment "one way or the other" on whether Mr Trump obstructed justice.
He wrote: "While this report does not conclude that the president committed a crime, it also does not exonerate him."
Instead, the special counsel laid out the evidence on both sides of the question.
According to Mr Barr, Mr Mueller left unresolved what he viewed as the "'difficult issues' of law and fact concerning whether the president’s actions and intent could be viewed as obstruction".
Barr made the decision over prosecuting obstruction
With no recommendation from Mr Mueller, Mr Barr said he then stepped in.
The attorney general, who was appointed by Mr Trump, said he and his deputy Rod Rosenstein decided there was not sufficient evidence to establish that the president obstructed justice.
That conclusion was based on Mr Mueller’s investigation, Mr Barr said. It was not a reflection of the justice department’s view that a sitting president cannot be indicted.
Mr Barr determined that none of Mr Trump’s actions amounted to obstruction and there was not sufficient evidence to show he acted with a "corrupt intent".
He also noted there was not an underlying crime involving Mr Trump.
The bar for prosecution over collusion was high
The letter sheds some light on how Mr Mueller approached the collusion question.
In assessing whether Americans committed crimes related to Russia’s election interference, Mr Mueller was looking for a specific agreement "tacit or express" between the Trump campaign and the Russian government.
Mr Barr said investigators did not find that, but his letter does contain a nod to some of the Trump campaign’s contacts with Russia, noting that Mr Mueller uncovered "multiple offers from Russian-affiliated individuals to assist the Trump campaign".
Grand jury witnesses have shown that Mr Mueller scrutinised a June 2016 meeting at Trump Tower involving a Russian lawyer.
The president’s eldest son, Donald Trump Jr, took the meeting even though it was described as a Russian government effort to help his father.
Trump Jr expected the meeting to produce derogatory information on Mr Trump’s Democratic rival, Hillary Clinton.
Court papers also show that Mr Mueller uncovered that a Maltese professor told a Trump campaign foreign policy adviser that the Russians had dirt on Mrs Clinton in the form of emails – a message passed along weeks before it became public that Democratic groups had been hacked.
Mr Trump was also trying to cut a business deal in Russia during the campaign, an effort that included his personal lawyer discussing the proposal with a Kremlin official.
But according to Mr Mueller, the Americans involved did not violate the law.
Is Trump out of the woods?
No - Mr Trump also plays a central role in a separate case in New York, where prosecutors have implicated him in a crime.
They say the president directed his personal lawyer Michael Cohen to arrange illegal hush-money payments as a way to quash potential sex scandals during the campaign.
New York prosecutors also are looking into Mr Trump’s inaugural fund.
Congressional investigations also are swirling around the president - Democrats have launched a sweeping probe over Mr Trump that threatens to shadow the president through the 2020 election season.
They are now also demanding that Mr Barr should turn over Mr Mueller’s confidential report and the underlying evidence he gathered in order for them to draw their own conclusions.
Democrats are also calling for Mr Barr to testify on Capitol Hill.