It was the trial of the century. Or so it seemed in April 1915, when ex-President Teddy Roosevelt and one-time New York Republican Party boss William Barnes squared off in a Syracuse, New York courtroom. Barnes was the plaintiff, Roosevelt the defendant. The charge was libel, based on a written statement Roosevelt had released to the newspapers, accusing Barnes and his Democratic Party counterpart, Charles Murphy, of collaborating in an “invisible government” built on an “alliance between crooked business and crooked politics.”

Before the trial was over, Roosevelt would occupy the witness chair for eight consecutive days, 38 ½ hours in all, perhaps the longest time that the famously energetic ex-president ever sat still. But true to form, he played to the jury as if it was his audience at a campaign rally, becoming so animated on the stand that the plaintiff’s lead attorney objected to his “gesticulation” and asked the judge to restrain him. The judge, knowing that was probably impossible, declined. Newspaper reporters, meanwhile, filled column after column of type with his every word.

Little more than a century later, the case is all but forgotten. “Despite the fact that it made headlines everywhere for six weeks, the trial has somehow become a footnote to history,” marvels Dan Abrams, who, with coauthor David Fisher, aims to change that in the new book Theodore Roosevelt for the Defense: The Courtroom Battle to Save His Legacy.

Abrams, who is also the chief legal-affairs correspondent for ABC News and host of “Live PD” on A&E, recently talked about the case with History.com.'

HISTORY: As you point out in the book, lots of trials have been hyped as the ‘trial of the century’—including the O.J. Simpson case, which you covered. What made Barnes v. Roosevelt rise to that level?

Dan Abrams: When you have a former president of the United States testifying for eight days, I think that inevitably you’re going to get widespread attention. But this wasn’t just any president, it was Teddy Roosevelt. And Teddy Roosevelt, whether you loved him or hated him, was a character.

READ MORE: 10 Things You May Not Know About Teddy Roosevelt

Now that the 20th century is behind us, do you have a pick for the true trial of the century?

It depends on how you define it, right? Is it the most important, or is it the most widely seen and followed? I don’t think there is a single “trial of the century,” but there are a handful. Lindbergh was certainly one of them, and the Simpson case is up there. But if you want to talk about most important, I’d say Bush v. Gore—not just the Supreme Court case, but the whole process working its way up to that because ultimately it decided who would be president.

Was it common for politicians to sue each other back then? Was it a particularly litigious era?

I wouldn’t say it was common for political insults to end up in the courts, but it was definitely a time when more people were suing for libel than today. The laws were less protective of defendants, and it was kind of the post-duel era, where dueling was no longer OK. So this is how people resolved their disputes.

Roosevelt had been out of the White House for six years at that point. What was at stake for him in the trial?

I think he thought he still had a political future and the result of this case could definitely have impacted that. But Roosevelt also took his probity very seriously. I think this case was very personal to him—not just because he was being sued, but because he was accused of being dishonest.

At one point in the book you quote Roosevelt telling reporters that he was thoroughly enjoying himself at the trial. Do you think that’s true, or was he just putting up a brave front?

I don’t think he enjoyed the fact that he was being sued, but he did enjoy speaking to reporters, and I think he enjoyed testifying. He was a man who liked to speak his mind.

READ MORE: How Teddy Roosevelt Crafted an Image of American Manliness

One thing that came up at the trial and might surprise readers today is how reluctant he had been to accept his party’s vice-presidential nomination in 1900. Why was that?

I think he saw the vice presidency as a dead-end job where he couldn’t do anything. He viewed himself as very active and proactive, and as vice president you had almost no official power. It really took a lot of convincing by the party and by [President William] McKinley himself to get him to do it.

In fact, at the time he said he’d rather be a history professor. Do you think he was serious?

Yes, I think he was serious about wanting to be a professor. He wrote an enormous number of books, he was a voracious reader and he took history very seriously.

READ MORE: Teddy Roosevelt's Bold (But Doomed) Battle to Change American Spelling

Without totally spoiling the book’s ending, the outcome of the trial seems to have rejuvenated Roosevelt’s political career, and yet he doesn’t appear to have done anything to capitalize on it.

I don’t know that it rejuvenated his political career, but it might have ended it had he lost. I think his decision not to run [for president] in 1916 was not surprising, given everything that was going on with the war. But he could have been a viable candidate in 1920 because many people considered him to have been right about World War I, right about Germany and right that the U.S. should have gotten involved earlier.

Of course, he died in 1919, so we’ll never know for sure. Were you surprised by any parallels to contemporary political life, such as Roosevelt’s attacks on the influence of money in politics, or his lambasting the two-party system for not providing a real choice for voters?

Yes, it’s striking that many of those same issues still exist today—party bosses, the two-party system, money in politics and all the rest. Of course, one of the biggest differences was that in New York at that time, senators were elected by the party bosses and not by the vote of the people. That was one of the big fights that actually brought about a change.

Your Roosevelt book follows an earlier one about a murder case involving Abraham Lincoln (Lincoln’s Last Trial). Are there other forgotten trial transcripts that you’re dying to get your hands on?

We have a deal for two more books. We haven’t announced what the third book is going to be yet, but we’re working in it.

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