His detractors should know that by undertaking to represent such a client, Sullivan is participating in a tradition older than the nation itself. The British soldiers who opened fire on a crowd of Bostonians in 1770, killing five, were among the most reviled men in the 13 colonies. Harvard alumnus John Adams, a patriot with aspirations for political office, agreed to defend them at trial, even though he knew that he was risking not only his reputation, but the safety of his family, because aggrieved Bostonians felt that their safety was implicated.

“In the Evening I expressed to Mrs. Adams all my Apprehensions: That excellent Lady, who has always encouraged me, burst into a flood of Tears, but said she was very sensible of all the Danger to her and to our Children as well as to me, but she thought I had done as I ought, she was very willing to share in all that was to come and place her trust in Providence,” he later wrote. Though he went on to sign the Declaration of Independence, and serve as vice president and president of the United States, he counted bolstering the principle that even people accused of heinous crimes deserve a vigorous defense as “one of the most gallant, generous, manly and disinterested Actions of my whole Life, and one of the best Pieces of Service I ever rendered my Country.”

Throughout U.S. history, criminal-defense attorneys have endeavored to conserve and apply that principle. And they’ve been subjected to attacks for so doing.

“Little more than half a century ago, mainstream lawyers were frightened away from defending alleged Communists who faced congressional witch hunts, blacklisting, criminal trials, and even execution,” Harvard Law’s Alan Dershowitz wrote. “Sen. Joseph McCarthy and the millions of Americans—including many lawyers, law professors, and bar association leaders––who supported this attack on ‘communist lawyers’ made it impossible for decent lawyers who despised communism but supported civil liberties and constitutional rights for all to defend accused Communists without risking their careers.”

Defense attorneys for Communists made many feel angry and unsafe.

More recently, lawyers who defended War on Terror detainees and later sought employment in the Barack Obama administration’s Department of Justice were smeared by prominent figures including Liz Cheney and Bill Kristol, who dubbed them “the al-Qaeda seven” and implied that they shared the enemy’s values.

Defense attorneys for al-Qaeda terrorists made many feel angry and unsafe.

In 2016, during the second presidential debate with Hillary Clinton, Donald Trump attacked his rival as unfit to lead because she once acted as the defense attorney for a man accused of raping a 12-year-old. (She thought he was guilty.) Defense attorneys for child predators make many feel angry and unsafe.