After two years and 200 interviews, the Senate Intelligence Committee is approaching the end of its investigation into the 2016 election, having uncovered no direct evidence of a conspiracy between the Trump campaign and Russia, according to both Democrats and Republicans on the committee.

But investigators disagree along party lines when it comes to the implications of a pattern of contacts they have documented between Trump associates and Russians — contacts that occurred before, during and after Russian intelligence operatives were seeking to help Donald Trump by leaking hacked Democratic emails and attacking his opponent, Hillary Clinton, on social media.

"If we write a report based upon the facts that we have, then we don't have anything that would suggest there was collusion by the Trump campaign and Russia," said Sen. Richard Burr, R-N.C., the chairman of the Senate Intelligence Committee, in an interview with CBS News last week.

Burr was careful to note that more facts may yet be uncovered, but he also made clear that the investigation was nearing an end.

"We know we're getting to the bottom of the barrel because they're not new questions that we're searching for answers to," Burr said.

Democratic Senate investigators who spoke to NBC News on condition of anonymity did not dispute Burr's characterizations, but said they lacked context.

"We were never going find a contract signed in blood saying, 'Hey Vlad, we're going to collude,'" one Democratic aide said.

The series of contacts between Trump's associates, his campaign officials, his children and various Russians suggest a campaign willing to accept help from a foreign adversary, the Democrats say.

By many counts, Trump and his associates had more than 100 contacts with Russians before the January 2017 presidential inauguration.

After two years and 200 interviews, the Senate Intelligence Committee is approaching the end of its investigation into the 2016 election, having uncovered no direct evidence of a conspiracy between the Trump campaign and Russia, according to both Democrats and Republicans on the committee.

But investigators disagree along party lines when it comes to the implications of a pattern of contacts they have documented between Trump associates and Russians — contacts that occurred before, during and after Russian intelligence operatives were seeking to help Donald Trump by leaking hacked Democratic emails and attacking his opponent, Hillary Clinton, on social media.

"If we write a report based upon the facts that we have, then we don't have anything that would suggest there was collusion by the Trump campaign and Russia," said Sen. Richard Burr, R-N.C., the chairman of the Senate Intelligence Committee, in an interview with CBS News last week.

Burr was careful to note that more facts may yet be uncovered, but he also made clear that the investigation was nearing an end.

"We know we're getting to the bottom of the barrel because they're not new questions that we're searching for answers to," Burr said.

Democratic Senate investigators who spoke to NBC News on condition of anonymity did not dispute Burr's characterizations, but said they lacked context.

"We were never going find a contract signed in blood saying, 'Hey Vlad, we're going to collude,'" one Democratic aide said.

The series of contacts between Trump's associates, his campaign officials, his children and various Russians suggest a campaign willing to accept help from a foreign adversary, the Democrats say.

By many counts, Trump and his associates had more than 100 contacts with Russians before the January 2017 presidential inauguration.

After it recently emerged that Trump campaign chairman Paul Manafort shared campaign polling data with a man the FBI says is linked to Russian intelligence, Warner called that the most persuasive evidence yet of coordination.

"This appears as the closest we've seen yet to real, live, actual collusion," he said on CNN.

No evidence has emerged, however, linking the transfer of polling data to Trump. Also unclear in court documents is Manafort's motive for sharing the information. Facing more than a decade in prison for bank and tax fraud, he has not been accused by Mueller of any crimes related to the 2016 election.

Burr, in the CBS interview, said the motivations behind the Trump campaign's interactions with Russians were in some cases impossible to discern.

"There's an awful lot of connections of all these people," he said. "They may not be connections that are tied to 2016 elections in the United States, but just the sheer fact that they have a relationship — it may be business. It may be Russian intelligence. It may be they're all on the payroll of Oleg Deripaska," he added, referring to a Russian oligarch tied to Putin who had business dealings with Manafort.

The final Senate report may not reach a conclusion on whether the contacts added up to collusion or coordination with Russia, Burr said.

Democrats told NBC News that's a distinct possibility.

"What I'm telling you is that I'm going to present, as best we can, the facts to you and to the American people," Burr told CBS. "And you'll have to draw your own conclusion as to whether you think that, by whatever definition, that's collusion."