The meeting matters because a special counsel and congressional committees are investigating Russian attempts to influence the 2016 election and whether the Trump campaign colluded with the Kremlin. When the Times first reported the story on Saturday, it called the revelation "the first public indication that at least some in the campaign were willing to accept Russian help." The probe has dogged and frustrated President Trump since he took office, and he has denied collusion with Russia.

Trump Jr. said the woman, whom The New York Times identified as Natalia Veselnitskaya , offered information about President Donald Trump's then-Democratic opponent Clinton, but the attorney's statements were "vague" and "made no sense." He said he determined that she had "no meaningful information," and he discovered that her "true agenda" was to discuss the Magnitsky Act, an American law meant to punish Russian human rights violators.

Trump Jr. met in June 2016 with the attorney, who turned out to be a Kremlin-connected lawyer. In a statement Sunday, he said he was told she might have information "helpful" to his father's presidential campaign . It is unclear if he knew who she was before the meeting, but Trump Jr. denies even knowing her name going into it.

Donald Trump Jr.'s meeting with a Russian lawyer who offered dirt on Hillary Clinton is significant as part of the Russia investigation — but it may not be enough to tip the probe on its own, a legal expert said Tuesday.

Special counsel Robert Mueller's investigators will certainly take interest in the meeting as a significant thread in the larger investigation, according to Jeffrey Cramer, a former assistant U.S. attorney for the Northern District of Illinois and managing director at Berkeley Research Group. But he said its significance ultimately hinges on whether Trump Jr. accepted the meeting knowing that Veselnitskaya had connections to the Russian government.

"The distinction matters because if he did know who she was, it allows investigators to conclude that the Trump campaign was willing to accept help from the Russians," he said. "It's not a home run, but it's another data point along the way."

The reaction from another legal expert was more severe on the ramifications if Trump Jr. knew he was getting information from a Russian government-linked source. Richard Painter, a former ethics lawyer for President George W. Bush and a frequent Trump critic, said doing so "borders on treason."

"This was an effort to get opposition research on an opponent in an American political campaign from the Russians, who were known to be engaged in spying inside the United States. ... This is a very, very serious situation. We should not treat this lightly," Painter told MSNBC on Sunday.

The meeting took place at Trump Tower in New York two weeks after Trump clinched the Republican presidential nomination. Cramer said it "defies logic" that Trump Jr. would take a meeting under those circumstances without knowing the woman's name.

Campaigns collecting opposition research from a foreign government is not a common practice.

The Times identified the intermediary who set up the meeting — who Trump called "an acquaintance I knew from the 2013 Miss Universe pageant" in Moscow — as Rob Goldstone, the head of an entertainment company.

Goldstone said in a statement to NBC News that his client and pop star Emin Agalarov asked him to set up the meeting between Trump Jr. and Veselnitskaya, who "apparently stated she had some information" about campaign contributions that Trump Jr. would want. Agalarov and his father develop real estate in Russia, and the elder Trump chose them to host the Miss Universe pageant in 2013, according to the Times.

"At the meeting, the Russian attorney presented a few very general remarks regarding campaign funding and then quickly turned the topic to that of the Magnitzky Act and the banned U.S. adoption of Russian children — at which point the meeting was halted by Don Jr. and we left," Goldstone said. "Nothing came of that meeting and there was no follow up between the parties."

The president's legal team has said Trump did not attend the meeting and did not have knowledge of it. Trump Jr., who acted as a surrogate and advisor for his father's presidential campaign, said he also invited the president's son-in-law Jared Kushner and then-campaign manager Paul Manafort to attend. He said the pair knew "nothing of the substance" about the meeting.

In a subsequent tweet Monday morning, Trump Jr. defended himself again, sarcastically saying he was "the first person on a campaign to ever take a meeting to hear info about an opponent." He added that the meeting "went nowhere" but he "had to listen."

Trump Jr.: Obviously I'm the first person on a campaign to ever take a meeting to hear info about an opponent... went nowhere but had to listen.

Cramer said Trump Jr.'s shifting story will also pique investigators' interest. He initially told the Times in March that he did not participate in campaign-focused meetings with Russian nationals.

When the Times first reported the meeting's existence Saturday, Trump Jr. admitted that it took place, but said it was primarily about an adoption program.

The Kremlin has denied knowing about the meeting, according to multiple reports.