Legal experts weigh in on emails released by Donald Trump Jr.

Donald Trump Jr. could have violated campaign finance law.

— -- After Donald Trump Jr. released screen shots of what he says is an email chain arranging a meeting between him and a Russian attorney who allegedly had damaging information about Hillary Clinton, ABC News spoke to legal experts about whether Trump broke any laws.

Trump posted on Twitter on Tuesday four pages of purported emails between him and music producer Robert Goldstone, who arranged the meeting with the Russian attorney, Natalia Veselnitskaya, saying in a statement that he did so "in order to be totally transparent." The email exchange appears to have begun on June 3, 2016, when Goldstone reached out to the eldest son of then-candidate Donald Trump.

The most relevant law, a campaign finance rule, makes it unlawful to "knowingly solicit, accept, or receive" a "contribution" from a foreign national or foreign government, according to experts. Violators can be fined by the Federal Election Commission (FEC), or if they act "willfully," they can be charged with a crime, even a felony.

One Republican lawyer told ABC News that whether Trump committed a crime depends on whether he solicited something "of value," adding that the case is worthy of additional investigation. The attorney said that while he thinks it is clear that Trump solicited something, since the definition for solicitation is very broad, he speculates that Trump will argue that the information he solicited was not of value.

Norm Eisen, a former ethics czar for the Obama administration and the co-founder of Citizens for Responsibility and Ethics, tweeted Tuesday that the meeting "clearly violates campaign finance law."

Richard Hasen, a professor at the University of California, Irvine School of Law, , believes that oppositional research on Clinton could be considered "something of value" under campaign finance laws. In his blog, he points to findings by the FEC that a list of activists' names, given to Bush-Cheney reelection campaign by Grover Norquist’s Americans for Tax Reform in 2004, and polling information given to a campaign in 1990, could qualify as non-monetary "contributions" that political campaigns are prohibited from soliciting or accepting from foreigners.

Another Republican attorney and a supporter of President Trump told ABC News that while receiving money or certain gifts from foreigners could violate the law, there was nothing of value suggested by these emails.

If Trump had asked for more research or for the Russian attorney to make herself available, then he may have broken the law, the attorney said, adding that Trump did not violate the law by simply taking a meeting.

Cornell law professor and Associate Dean Jens David Ohlin, an expert in criminal law, told ABC News that the emails released by Trump establish that the campaign was not only aware of, but was directly involved in, attempts to coordinate with the Russian government in their efforts to meddle in the election.

"It’s a shocking admission of a criminal conspiracy," Ohlin said. "The conversation will now turn to whether President Trump was personally involved or not. But the question of the campaign’s involvement appears settled now. The answer is yes."

Common Cause, a group that describes itself as a "nonpartisan grassroots organization dedicated to upholding the core values of American democracy," filed complaints with the FEC and Department of Justice on Monday. In a statement, the group's Vice President for Policy and Litigation, Paul S. Ryan, said that if the emails "are not a hoax, they are the smoking gun showing that Donald Trump Jr. illegally solicited a contribution from a foreign national -- in the form of opposition research against Hillary Clinton."

"Whether or not he actually received that information does not matter in the eyes of the law," Ryan said. "Trump’s solicitation of the information is what constitutes the violation."

Ryan continued that it is "shocking" that Trump did not "immediately contact federal authorities when he was offered information, supposedly from the Russian government."

Ann Ravel, the most recently departed Commissioner of the Federal Election Commission, told ABC News that she believes the situation is "worthy of an investigation," she believes the FEC "isn't going to do anything about it" and that the Justice Department is "unlikely to prosecute."

Ravel was appointed by former President Barack Obama and was slated to remain as FEC commissioner until April, but she left early in March, telling ABC News she resigned because she didn't think it was possible to "enforce or follow the law" at the FEC.

ABC News' Aaron Katersky contributed to this report.