The long-awaited testimony of former Acting Attorney General Sally Yates on former National Security Adviser Michael Flynn offered valuable insight on President Trump's failure to dismiss the compromised former general until forced to do so by embarrassing press reports, and on Mr. Trump's repeated attempts to shift blame to former President Barack Obama.
Ms. Yates, a veteran civil service official who was herself fired by Mr. Trump for ordering the Justice Department not to defend in court the new president's ban on travelers from certain Muslim nations, told the Senate Judiciary Committee that the Trump White House brushed off her warning that Mr. Flynn was vulnerable to Russian blackmail.
In her calm and self-controlled appearance, Ms. Yates recounted how she had informed White House counsel Donald McGahn that Mr. Flynn had lied to Vice President Mike Pence about his conversations with Russian Ambassador Sergey Kislyak and expected the White House to take swift action to remove Mr. Flynn.
Instead, she said, Mr. McGahn summoned her to his White House office a second time to inquire why she was so concerned that one Trump administration official had lied to another one. She told him that Russian intelligence "likely had proof ... that created a compromise situation" wherein Mr. Flynn "could be blackmailed." She told White House officials, she said, "so that they would take action."
However, nothing was immediately done to remove Mr. Flynn as the national security adviser, even after reports that Mr. Obama himself had warned Mr. Trump of the peril of appointing Mr. Flynn to the super-sensitive post.
Rather, White House chief of staff Reince Priebus and press secretary Sean Spicer dismissed the warning as a mere "heads-up." Mr. Spicer sought to make Mr. Obama culpable by noting that Mr. Flynn much earlier had been vetted by the Obama administration in the course of Mr. Flynn's appointment to run the Defense Intelligence Agency, a post from which Mr. Obama fired him in 2014.
Mr. Trump himself also jumped in with a favored diversionary tactic, tweeting before the Senate committee hearing: "Ask Sally Yates, under oath, if she knows how classified information got into the newspapers soon after she explained it to W.H. Counsel" -- that is, Mr. McGahn. Subsequently, Republican committee chairman Sen. Charles Grassley of Iowa dutifully did ask her, to which she denied leaking any information to reporters or knowing anyone who might have.
Other Republicans on the committee challenged Ms. Yates on the appropriateness of her refusal as the acting attorney general to defend Mr. Trump's travel ban. Sen. John Cornyn of Texas, after noting he had voted earlier for her confirmation as a deputy attorney general, said he was "enormously disappointed" that she had in effect overruled him on the travel ban, on the grounds it violated the constitutional protection of freedom of religion.
Ms. Yates, obviously prepared for the question, reminded Mr. Cornyn that one of his colleagues, Jeff Sessions, now the attorney general, pointedly asked in her confirmation hearing if the president asked her to do "something that was unlawful or unconstitutional ... or even just that would reflect poorly on the Department of Justice, would I say no? ... That's what I promised you I would do, and that's what I did."
When Sen. Ted Cruz of Texas repeated the question, she dispatched it with "I did my job."
Republican Sen. John Kennedy of Louisiana, a freshman who displayed all the guilelessness of his experience, sarcastically inquired of Ms. Yates: "Who appointed you to the Supreme Court?" She held her ground, saying: "I believed any argument (the Justice Department) would have to make in its defense would have to be grounded in the truth. ... We would have to argue that it had nothing to do with religion."
Whatever the ultimate outcome of the Russian interference with the 2016 presidential election and the role of Gen. Flynn's connections with the Russians, Sally Yates' testimony that she brought the matter to Mr. Trump's attention has already raised speculation of a political future for her. Democratic Mayor Kasim Reed of Atlanta has urged her to run for governor of Georgia next year, apparently without evidence she has any such interest.
What is clear, though, from Ms. Yates's tenacious determination to stick to her guns as a law enforcement official is that she has already proved her value in that chosen arena.
Jules Witcover's latest book is "The American Vice Presidency: From Irrelevance to Power," published by Smithsonian Books. You can respond to this column at email@example.com.