WASHINGTON — When Supreme Court Justice Clarence Thomas headlined a 2017 program at McLennan Community College in Texas, his hosts had more than a speech in mind. Working with the prominent conservative lawyer Ken Starr, school officials crafted a guest list for a dinner at the home of a wealthy Texas businessman, hoping an audience with Thomas would be a reward for school patrons — and an inducement to prospective donors.Before Justice Elena Kagan visited the University of Colorado’s law school in 2019 …