The historic second impeachment trial of Donald Trump begins today in the Senate. The proceedings will decide whether to hold Trump accountable for inciting the deadly insurrection on the U.S. Capitol on January 6, which was aimed at stopping lawmakers from counting the Electoral College votes.

Tuesday’s debate will focus on the constitutionality of impeaching a former president. The Trump defense team is relying heavily on a law review article by Michigan State University professor Brian Kalt, whose work was cited 15 times in a legal brief filed by Trump’s lawyers on Monday. Kalt told NPR his work is being misrepresented.

Brian Kalt: “The worst part is the three places where they said I said something, when in fact I said the opposite.”

Lawyers for the defense also plan to argue Trump was exercising his First Amendment rights when he made comments like these to the thousands of people who rallied outside the White House on the day of the failed insurrection.

President Donald Trump: “We fight like hell. And if you don’t fight like hell, you’re not going to have a country anymore.”

House impeachment managers and Trump’s defense lawyers will each be given 16 hours over two days to make their arguments. The trial could end early next week. After headlines, we’ll get the latest on Trump’s second impeachment trial.