National security adviser H.R. McMaster pauses during a briefing at the White House in Washington on May 16. (Susan Walsh/Associated Press)

In his May 21 Outlook essay, “H.R. McMaster and the duty of dereliction,” Carlos Lozada gave voice to a disappointment I have been feeling. I recently read Lt. Gen. H.R. McMaster’s well-researched book on the deceit and narcissism of the Johnson administration that led to the Vietnam War and the nation’s resulting loss of confidence in our government in the 1960s. As Mr. Lozada pointed out, Mr. McMaster condemned Lyndon B. Johnson as one “with a ‘real propensity for lying’ . . . obsessed with loyalty . . . and focused on his political fortunes at the expense of the nation’s needs,” as well as “paranoid about dissent.”

The parallels to our current situation were striking. So it was with great relief that I greeted the hiring of Mr. McMaster as national security adviser to President Trump. I had hope that the general’s “contempt . . . toward those who do not speak clearly and honestly . . . with the president and lawmakers” would save us from the cliff our deceitful and impetuous president was leading us toward. And then Mr. McMaster walked out onto the White House lawn and tersely defended Mr. Trump’s conversations with Russian officials. My hero had become a traitor to every value he had held in his book. I could only put my head in my hands and cry.

Lori Brown, Woodbridge