Robert Mueller's report represents a thorough, insightful and professional analysis of Russia's interference with the 2016 presidential election. However, it was never intended to present the final word on whether President Donald Trump, his campaign aides and executive officials in the Trump administration engaged in illegal and criminal activities. The report marks an important but distinctly partial step. As made clear in the introduction to Volume 1: "A statement that the investigation did not establish particular facts does not mean there was no evidence of those facts." New information will shed further light on whether Trump and other individuals pursued activities that placed their financial and political ambitions over the national interest and the need to protect our constitutional system.

The report provides extensive detail on what is called the Trump Moscow project. Between approximately Oct. 13, 2015, and Nov. 2, 2015, the Trump Organization (through its subsidiary Trump Acquisitions) completed a letter of intent for a Trump Moscow property. Signed by Trump for the Trump Organization, the letter was "intended to facilitate further discussions" in order to reach a mutually acceptable agreement. The letter contemplated an extensive development with residential, hotel, commercial and office components, calling for approximately 150 first class, luxury residential condominiums as well as one first class, luxury hotel consisting of approximately 15 floors and containing no fewer than 150 hotel rooms.

The Mueller report states that Michael Cohen recalled that both he and Trump wanted the Moscow project "to succeed and that Trump never discouraged him from working on the project because of the campaign." The Trump Organization "stood to earn substantial sums over the lifetime of the project, without assuming significant liabilities or financing commitments." To Cohen, the Trump Tower Moscow "was potentially a $1 trillion deal." The report states that Cohen remembered that Trump would be willing to travel to Russia if Cohen could "lock and load" the deal. Despite efforts by both sides, the Moscow project was eventually cancelled. The report notes that Trump responded to questions about possible connections to Russia "by denying any business involvement in Russia—even though the Trump Organization had pursued a business project in Russia as late as June 2016."

FBI director Robert Mueller listens to comments and questions from the Senate Judiciary Committee during a hearing on FBI Oversight. December 6, 2006.

When WikiLeaks on July 22, 2016, released hacked Democratic National Committee emails, doing great damage to the election chances of Hillary Clinton, the Trump campaign publicly denied suggestions that Russia was seeking to aid candidate Trump. In Volume 2, the Mueller report points out that four days later, Trump tweeted that it was "crazy" to suggest that Russia was "dealing with Trump" and he had "ZERO investments in Russia." The report further states that in a news conference on July 27, 2016, Trump repeated five times: "I have nothing to do with Russia." He did acknowledge he had a major developer wanting to develop property in Moscow but "we decided not to do it." Mueller's report states that in January 2017, the U.S. intelligence community publicly concluded "with high confidence" that Russia had intervened in the presidential election with the goal of harming Clinton and clearly preferring Trump.

The difficulty in reaching a clear judgment on Trump's culpability is due in part to the need to redact material in the report to protect grand jury secrets and other privileged matter. Of special interest, but little discussed in public comments about the report, is the term HOM, standing for "harm to ongoing matter." At key stages in the report, sentences, paragraphs and even entire pages have been blacked out so as not to expose and interfere with ongoing research. When those investigations are complete, they will help illuminate what we can now only engage in speculation.

A number of federal courts are in the midst of litigation that may reveal additional evidence about Trump and his advisers. Testimony by Cohen before the House Oversight Committee on Feb. 27 identified a number of individuals who are personally knowledgeable about Trump. Relying on that advice, the committee has received thousands of new documents. As information continues to be made available, we will have a better understanding of why Trump chose to react as he did. From the start, he publicly declared full innocence for himself and his supporters with regard to Russia's interference in the 2016 election. Given those statements, it would seem reasonable for Trump to encourage Mueller to conduct a full and vigorous inquiry. Yet Trump on a regular basis characterized the investigation as a "witch hunt." That hunt continues.

Louis Fisher is scholar in residence at The Constitution Center at POGO. From 1970 to 2010 he served as senior specialist in separation of powers at Congressional Research Service and specialist in constitutional law at the Law Library of Congress.