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Chaos swept over college campuses around the nation Thursday, as the ousters of the embattled University of Missouri system’s president and chancellor earlier this week were followed by dozens of other student protests calling for more faculty and staff heads to roll.

A popular professor at Missouri said he resigned Wednesday after students lashed out at him for pledging to give a scheduled exam amid spiraling protests, but the university said Thursday it rejected his resignation.

The Dean of Students at Claremont McKenna College in California, Mary Spellman, resigned in a letter to the community Thursday, after some at the school called for hunger strikes over what they perceived as a lack of support for students of color.

Students at Ithaca College in New York, Yale University and Vanderbilt University in Tennessee were also calling to ax administrators, and even more campuses were pledging solidarity with the burgeoning social justice movement.

As many as 20 other campuses around the country were planning marches Thursday, including St. John’s, Syracuse and Columbia universities in New York, Harvard and the University of Wisconsin-Milwaukee. Disaffected students at Loyola University in Chicago and the University of Michigan were preparing a list of demands and threatening action, according to The Seattle Times. Black alumni at Georgia Tech were crafting a letter to that university’s president, urging a continued commitment to diversity.

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    A Change.org petition signed by about 1,500 people called for the job of Vanderbilt University professor Carol Swain for “unprofessional intimidation on social media” and “discriminatory practices in the classroom.”

    The spreading unrest has dominated the media and even seeped its way into the presidential race, with Republican candidate Dr. Ben Carson, who attended Yale, lashing out at demonstrators during an appearance on “The Kelly File” on Wednesday.

    "Well we're being a little bit too tolerant, I guess you might say, accepting infantile behavior,” Carson said. “I don't care which side it comes from. To say that I have the right to violate your civil rights because you're offending me is un-American. It is unconstitutional. And the officials at these places must recognize that and have the moral courage to stand up it. Because if they don't, it will grow, it will exacerbate the situation and we will move much further toward anarchy than anybody can imagine, and much more quickly.”

    The school at the focal point of the current crisis, the University of Missouri, hired an interim system president on Thursday afternoon. Mike Middleton previously attended Missouri as a student and also served as a faculty member and administrator. Middleton, who is black, said he felt marginalized "every day" in each of those roles.

    "It's so subtle," Middleton said. "I think women understand it. I think people with a sexual orientation that is not a male-centered perspective on sexuality understand it. I think other people of color understand it. I think folks in power, in the majority, who have never lived it and have never experienced it have difficult understanding it the way those of us who have been minoritized do.

    "But it is just the feeling of not being heard, not being respected," he said. "Being placed at the margins of what's really happening in the world. And it happens inadvertently. Nobody is really to blame for this."

    Middleton will attempt to hold together a fracturing university system. Earlier this week, an associate professor teaching nutrition and exercise tried to resign when angry students accused him of insensitivity. The administration rejected his attempt, a spokesperson told FoxNews.com on Thursday.

    Dale Brigham, who has been described by previous students in glowing terms such as a "sweetheart" and "adorable," had emailed students that he was canceling an exam and quitting his post in response to a backlash from current students upset that he wouldn't delay a test.

    “The exam is canceled,” Brigham wrote on Wednesday. “No one will have to come to class today. And, I am resigning my position.”

    Some students were upset that Brigham initially refused to postpone the test amid the wave of protests, which have been mostly peaceful, but have also brought much of ordinary life on campus to a grinding halt. Some students apparently feared coming to class could be dangerous.

    Brigham initially responded to students’ request to delay the exam with an email in which he urged them not to “give in to bullies.”

    “If you don’t feel safe coming to class, then don’t come to class,” Brigham wrote to his class on Tuesday. “I will be there, and there will be an exam administered in our class.

    "I made a mistake, and I do not want to cause further harm”

    — Dale Brigham

    “If you give in to bullies, they win. The only way bullies are defeated is by standing up to them. If we cancel the exam, they win; if we go through with it, they lose. I know which side I am on. You make your own choice.”

    Professor Dale Brigham tried to resign following an email flap but the University of Missouri rejected the offer, the school told FoxNews.com. (University of Missouri)

    Brigham could not be reached for comment on whether he intends to follow through on his vow to leave the school. While known as a popular instructor, his call to stand up to threats and come to class did not sit well with some minority students in Brigham’s class.

    “My teacher had the nerve to email me, ‘If we cancel class, then we let the bullies win,’” one sophomore tweeted. “Like this is a game or something.”

    Brigham apologized to some students Tuesday evening, telling at least one student, who posted what appeared to be a copy of Brigham's email to Twitter, that he would offer the exam as scheduled Wednesday but also offer a make-up test.

    “I could have and should have used much better words in trying to say that we must stand up to hatred and not let those kind of people who make threats run our lives,” Brigham said in the email. “Obviously, I wrote poorly.”

    But by the following day, Brigham had gone even further, canceling the exam outright and offering his resignation, which was eventually not accepted.

    “I am just trying to do what I think is best for our students and the university as an institution,” Brigham told KOMU8News. “If my leaders think that my leaving would help, I am all for it. I made a mistake, and I do not want to cause further harm.”

    Protests at the University of Missouri have already led to the resignations of system President Tim Wolfe and Chancellor R. Bowen Loftin. Assistant Prof. Melissa Click, who appeared in a viral video obstructing a journalist from filming protests, resigned her courtesy appointment to the journalism school but is still ostensibly employed by the university. A Missouri spokesperson said Wednesday the school would not comment on the employment status of its professors.

    Brigham is a seemingly well-liked professor, who earned a 5.0 rating and "A" grade in 59 reviews on ratemyprofessors.com. Students who commented used terms such as "adorable" and "nicest" to describe Brigham.

    A Ph.D. in human nutrition, Brigham has served as a guest lecturer, presented dozens of seminars and workshops and spoken at numerous conferences. In addition to a lengthy list of published creative works, he has an extensive number of peer-reviewed publications. Among several honors, Brigham received awards for teamwork in 2006 and 2007, and was awarded the 1995 Penn State Continuing and Distance Education Program Development Award. He served as an honorary coach for men’s basketball, women’s softball, women’s gymnastics and men’s baseball. Active with student organizations, he’s been a faculty advisor for the Triathlon Club, Waterski and Wakeboard Club and Students Walking Students. Brigham also functioned as a representative for numerous physical activity campaigns.