The letter also does not indicate whether the attorneys also reviewed the Trump Organization’s returns in preparing it, or whether the company has Russian assets, debts, or other ties that might not appear in Trump’s personal tax returns. The few exceptions named might not be the only ones that exist.

“One could very much read this language in legalese and not feel at all convinced that Russian interests do not have leverage over the president,” said Michael Knoll, Theodore K. Warner Professor of Law and Professor of Real Estate at the University of Pennsylvania Law School.

For example, the letter doesn’t define several key terms. “Are they being technical with the language, or are they being straightforward with us?” Knoll asked. “I guess the assumption should be that they’re being technical. What it means by Russian person or entity does not seem that it excludes basically shell non-Russian entities.”

So, for example, a Russian could establish a pass-through company in the United States, the Cayman Islands, Cyprus, or any number of places, and then do business with Trump or the Trump Organization. That might not strictly speaking constitute a Russian entity, but for the purposes of the conflict-of-interest questions at the heart of Trump’s dealings, it would remain equally concerning.

Trump or his company could also work with Russians on a concern that was in neither the U.S. nor Russia that might not be covered by the letter. He could also have interests in companies that he and the Trump Organization did not control. Trump has frequently franchised his name to projects around the globe.

The Wall Street Journal’s Rich Rubin reported on similar concerns. “A Russian would not lend directly to Trump or his businesses,” Steve Rosenthal, a tax lawyer and senior fellow at the Tax Policy Center in Washington, told Rubin. “A Russian would, for example, fund a Cyprus corporation, which would lend to Trump or his businesses, possibly through other intermediary entities.”

The letter also does not indicate which years of taxes were covered, though it would not cover his finances since assuming the presidency. The disclaimer that Trump’s “tax returns do not reflect” these things leaves open the possibility of investments, loans, or other financial ties not covered in the returns. Trump could also potentially have losses, but not income, in Russia.

Dillon also helped Trump devise a plan to answer worries about conflicts of interest between his business and his presidential administration, and she appeared at a January press conference announcing the plan. Most independent ethics experts, however, have rejected that set-up as inadequate. Morgan Lewis was named the 2016 Russia law firm of the year by the research group Chambers and Partners.

During a Senate hearing on Monday, former Director of National Intelligence James Clapper was asked whether he’d ever seen anything about one of President Trump’s business interests in Russia that concerned him. Clapper declined to answer, saying it could have bearing on an ongoing investigation. Senator Lindsey Graham, chair of the Senate Judiciary Committee subcommittee on crime and terrorism, said he wanted to learn more.