“I did nothing in particular, and I did it very well.”

— Chief Justice William Rehnquist

“All of the weight of his office and his influence were brought to bear to save Johnson.”

— Rep. James A. Garfield

As the impeachment trial played out in the Senate chamber this week, most Americans were paying attention to the arguments of the House Managers or the president’s defense team. Others were focused on questions posed by individual senators. Later in the week came the pivotal question of whether witnesses would be called to testify or to give deposition testimony that would be presented in writing. Lawyers, on the other hand, might have been forgiven if their attention was instead drawn to Chief Justice John Roberts.

Article II, Section 3 of the United States Constitution, defining the powers of the United States Senate, says that when the House of Representatives issues articles of impeachment against a president, the Senate “shall have the sole power to try” them. But there is one twist that applies only when the federal officer impeached holds the highest office in the land — in those circumstances, “the Chief Justice shall preside.”

Prior to this year, only two chief justices of the United States Supreme Court have ever been called to do so. Ohioan Salmon Chase presided over the 1868 trial of Andrew Johnson, and William Rehnquist presided over the 1999 trial of Bill Clinton. Chase and Rehnquist could not have been more different in their handling of their Constitutional duties.

Rehnquist was notoriously stoic, and rarely gave public comment except in delivering his opinions in cases and speaking about legal issues. But from his writings to friends and colleagues, both contemporaneous to the trial and afterward, and released after his death in 2005, we know that he did not look upon the Clinton trial as particularly enjoyable or desirable.

He wasn’t particularly enamored with the political wrangling of the senators. He wrote to one friend that, “It is an historic occasion, and it has given me a chance to see the Senate firsthand,” but penned to another, “the trial is in one sense an unwelcome burden … I have been relieved of none of my responsibilities here at the Court.”

He was also disappointed with the salacious nature of the allegations against the president. When asked by another friend whether he had watched a television interview of Monica Lewinsky, he replied, “I couldn’t bring myself to read or watch any of the “Monica’ interviews — what a sad commentary on the country that 69 million people would watch the television presentation!”

Chief Justice Chase’s handling of the Johnson impeachment could not have been more different, but then Chase himself could not have been much more different from Rehnquist.

Chase never coveted his role as a Supreme Court justice, and having been governor of Ohio, a member of the Senate, and Treasury secretary, he was a far more political figure than Rehnquist would ever have dreamed of being.

More importantly, one thing that Chase very much wanted was to be president. He sought the Republican nomination in 1860, losing out to Abraham Lincoln. Honest Abe appointed him Treasury secretary to help maintain support of the Radical Republicans, but was keenly aware that Chase was maneuvering to possibly run for the nomination in 1864. So when Chase, for the third time, threatened to resign his cabinet post, Lincoln accepted his resignation and attempted to tuck him away in the Supreme Court chambers.

As such, Chase saw his impeachment duties as a way to improve his chances to become president in 1868, this time as a Democrat. A Johnson conviction would throw a roadblock in his way, because Johnson, having risen from the vice presidency upon the assassination of Lincoln, had no VP, and one of Chase’s rivals would ascend to the White House if impeachment was successful.

Throughout the trial, several senators and members of the House, including Ohio’s own James Garfield, a future president, lamented the active, and seemingly partisan role that Chase took in the trial. He campaigned to have the true powers of a judge in a legal proceeding — to rule on process, to decide the admissibility of evidence. He even campaigned to be permitted to break all tie votes, including the ultimate question of conviction and removal.

In the end, Johnson was acquitted by one vote on each of the articles of impeachment. Chase’s views toward suffrage for former slaves were not palatable to the Democratic Party of 1868. Horatio Seymour of New York got the nomination (over his strenuous objections) and lost the election to Ulysses Grant. Chase continued as chief justice until his death at age 65, following a stroke in 1873.

Ironically, we need not wonder what Chief Justice Rehnquist might have thought about Chief Justice Chase’s handling of the 1868 impeachment. That’s because Rehnquist quite literally wrote the book on the subject. In 1992 he penned “Grand Inquests” about the Johnson trial. The book remains in print and is available online and from independent booksellers everywhere.