In his 1955 bestseller, Profiles in Courage, John F. Kennedy, then a Senator from Massachusetts, recounted the histories of several former members of the U.S. Senate whom he held out as exemplars of what he believed to be the highest civic virtue—political courage. In the book's final chapter, Kennedy famously wrote: "For without belittling the courage with which men have died, we should not forget those acts of courage with which men … have lived … . A man does what he must—in spite of personal consequences, in spite of obstacles and dangers and pressures—and that is the basis of all human morality."

I recently had occasion to reread a chapter in Kennedy's masterpiece, the one concerning Edmund Ross, the Senator from Kentucky whose deciding vote during the impeachment trial of Andrew Johnson led both to Johnson's acquittal and the end of Ross' career. It speaks directly to the recent outcome in Donald Trump's impeachment trial and about the Republican members of the Senate responsible for it.

At issue in Johnson's impeachment trial was the Tenure of Office Act. Enacted over Johnson's veto in early 1867, it prevented the president from removing from office any executive branch official whose position had initially required Senate confirmation. Johnson, who like Lincoln had sought reconciliation with the South, feared that Edward Stanton, Lincoln's appointee as Secretary of War, would align himself with the Radical Republicans who sought to impose a harsh military rule over the vanquished Confederacy, and consequently, in clear violation of the Tenure of Office Act, fired him. The Radical Republicans, eager for an excuse to rid themselves of Johnson, saw to it that he was impeached as a consequence.