"[Cornel] West said in an interview with The New York Times last week that he did not know why his request to be considered for a tenured post had been rebuffed..."

"... but that he thought it could have something to do with his age and his support for the Palestinian cause, which he called a 'taboo' issue at Harvard." 

From "Cornel West Is Leaving Harvard After Tenure Dispute/The public intellectual and professor of African-American studies will head to Union Theological Seminary in New York" (NYT)(excellent photo of West at the link). 

And here's the article from last week: "Cornel West Is in a Fight With Harvard, Again/The popular professor, who left Harvard in 2002 after a dispute with its president, says he may leave again if the university does not grant him tenure." 

West rose to prominence with his 1993 best-selling book, “Race Matters,” followed by another best seller, “Democracy Matters.” He graduated from Harvard in 1973 and was recruited to its faculty in 1994 as part of a “dream team” to help rebuild the foundering African-American studies program. Over the years, he branched out from academia to advise or campaign for presidential hopefuls like Bill Bradley, Ralph Nader, Al Sharpton and most recently Bernie Sanders. He dabbled in hip-hop and played “Councillor West” in two Matrix movies. An album he collaborated on, “Four Questions,” is up for a Grammy.

Dr. West says the tenure issue arose when he came up for his five-year employment review recently. The faculty committee that oversaw that review recommended that his position of Professor of the Practice be converted to a tenure job, people familiar with the committee’s work said. Although he had been offered more money and an endowed chair, the dispute, Dr. West said, is not about money. (Nontenured professors can sometimes make more than tenured ones.)

The last time Dr. West clashed with Harvard’s administration was in 2001, when Mr. Summers, a former treasury secretary in the Clinton administration, took over as the university’s president, vowing to imbue the place with creative tension and to curb rampant grade inflation. Mr. Summers suggested that Dr. West was spending too much time on outside activities and not enough time on serious scholarship and teaching in the classroom, according to accounts at the time. An aide to Mr. Summers said at the time that it was all a “terrible misunderstanding.”

But Dr. West would not be placated and left for Princeton in April 2002. On the way out, he called Mr. Summers a bully and “the Ariel Sharon of American higher education,” a characterization criticized as having anti-Semitic overtones.

By the time Dr. West returned to Harvard in 2017, Mr. Summers was long gone. Harvard’s current president, Mr. Bacow, “actually has some decency,” Dr. West allowed. He said he is mystified as to why he would not be given a tenure review, but offered some possibilities: a reluctance to grant a coveted position to someone of advancing age, whose best work might be assumed to be behind him, and concerns that his support for the Palestinian cause might offend the prevailing orthodoxy and donors....