As the House Judiciary Committee takes up the momentous task of drafting articles of impeachment against President Donald Trump, a book written by one of the committee’s temporary hires offers clues about what allegations those articles could contain.

Joshua Matz, who is on leave from the boutique firm Kaplan Hecker & Fink as he works on the impeachment inquiry, co-authored a book with Harvard’s Laurence Tribe in 2017 titled “To End a Presidency: The Power of Impeachment.”