The petition called Cornyn's presence an "insult" to Texas Southern and other HBCUs (historically black colleges and universities) and suggested that students have a right to boycott their own graduation ceremony if the university kept Cornyn as speaker against their wishes.
The university's capitulation has drawn Texas Southern into the debate about free speech at U.S. colleges and universities that has stirred controversy several times when conservative speakers have planned to set foot on campus.
Education Secretary Betsy DeVos was booed as she spoke earlier this week at the commencement ceremony of Bethune-Cookman University, another historically black school. Administrators there did not act on petitions asking that DeVos not be allowed to speak, according to The Washington Post.
Instead, DeVos had to raise her voice as she thanked mothers who attended the ceremony. Moments later, about 380 students turned their backs on her.
Earlier this year, Berkeley administrators flip-flopped on a decision to let Ann Coulter speak on campus over safety concerns surrounding student protests. Coulter declined their second offer and roasted the California university officials in the media and on Twitter.
At Texas Southern, more than 800 people had signed the petition asking administrators to drop Cornyn as a commencement speaker. By Saturday morning, organizers had declared victory.
"The decision to host Mr. Cornyn, as a keynote speaker sends the message that the policies and views he has advocated and supported, including both discriminatory policies and politicians, are acceptable by the university and subsequently the student body," says the petition.
It ticks off a list of Cornyn's policy stances: He voted for DeVos for U.S. Education secretary and against expanding the Children's Health Insurance Program. And he voted in favor of requiring a voter ID in federal elections, a move critics say makes it harder for blacks and other minorities to vote.
Trump's administration worried some HBCU leaders this month when he released a statement that some interpreted to mean a key funding source historically black colleges and universities might not be constitutional. A few days later, Trump said in a statement that his previous comment "does not affect my unwavering support for HBCUs and their critical education missions."
Cornyn is the second-ranking Senate Republican and has been more vocal in his support of Trump in recent weeks.
He was one of four people scheduled to interview Saturday to serve as the FBI's new director, after James Comey was fired abruptly.