There was an intriguing moment in Fiona Hill’s testimony before the House Intelligence Committee Thursday morning—one that had little to do with the Ukraine scandal but much to do with deeper, more troubling aspects of Donald Trump’s presidency.

It came when Democratic counsel Daniel Goldman asked Hill if Trump’s famous July 25 phone conversation with Ukrainian President Volodymyr Zelensky was typical of other phone calls that Hill had monitored as the National Security Council’s top Russia specialist, a job she held for two years before resigning in July.

Goldman may have expected Hill to reply that the call was highly unusual, just as other witnesses have testified. Instead, Hill declined to answer the question, saying that presidents’ conversations with foreign leaders fall under executive privilege. Goldman noted that the call with Zelensky had been declassified. Hill said she would talk about that call, but would not compare it with others.

The counsel turned to other matters; other calls weren’t so important to the inquiry at hand. But why was Hill so reticent? Couldn’t she have said that the call was unusual without revealing the contents of other calls? One inference might be that the call was, in fact, not so unusual.

Michael McFaul, who had Hill’s job under President Barack Obama before he was appointed ambassador to Moscow, tweeted one explanation:

Unlike most, Fiona Hill HAS heard many calls from Trump just like the Trump-Zelensky call! That’s why she wisely just invoked executive privilege. Would love to hear someday about the Trump-Putin calls.

Most of the Trump phone conversations that Hill, as the NSC’s Russia specialist, heard would have been calls with or about Russian President Vladimir Putin. One can infer from Hill’s response that, in at least some of those calls, Trump was requesting or offering the same sort of “favors” or sketchy transactions that he was asking of Zelensky. Trump might seriously believe his call with Zelensky was “perfect” because he had made many similar calls, and no one had protested them.

In 25 years or so, the records of Trump’s phone calls will be declassified, just like those of presidents from Dwight Eisenhower on. The ensuing history books about the Trump era may unveil an even darker time than what we’re witnessing now, which of course is plenty dark. As Congress weighs whether this president should be ousted now, for the good of the nation, it would be useful if somehow we could read some of these records now.