This book was written, over the course of more than a year, in the midst of an involuntary career change. I held the position of U.S. Attorney for the Southern District of New York (SDNY) for seven and a half years, extended beyond the usual term at the personal request of President-elect Donald J. Trump on November 30, 2016, soon after his election. Then, on March 11, 2017, I was abruptly fired by President Trump.

Before I left that office, the crises were many and since then they have been and continue to be frequent, even constant. The rule of law and faith in the rule of law, the state of judicial and prosecutorial independence, the meaning and primacy of truth—all are in question and under fire in numerous ways.

Phrases and concepts like “the rule of law” and “due process” and “presumed innocent” seem to do service these days more as political slogans than as bedrock principles. Other honored precepts appear to be slipping too. It seems preferred these days to demonize one’s opponents rather than engage them, to bludgeon critics rather than win them over. There is a creeping con¬tempt for truth and expertise. Rigor is wanting everywhere. We swim in lies, never corrected. And the concept of justice seems turned on its head—holding different meaning depending on whether you are a political adversary or ally.

Certain norms do matter. Our adversaries are not our enemies; the law is not a political weapon; objective truths do exist; fair process is essential in civilized society.

It turns out that the law has something to teach us about truth, dignity, and justice. About how to resolve disagreements and disputes—with reason and evidence rather than taunts and character assassination.