Conservative political commentator Pat Buchanan has been fired from left-leaning news network MSNBC after more than four months of suspension, the longtime contributor revealed Thursday night.

In a lengthy screed published to his personal website, Buchanan tore into his former employer of 10 years for what he called "an undeniable victory for the blacklisters," in which the former Nixon aide calls out MSNBC for caving to organizations like the African-American advocacy group Color of Change, LGBT advocates with Human Rights Campaign, Jewish advocates at The Anti-Defamation League and progressive media watchdog Media Matters for America.

MSNBC President Phil Griffin said recently that Buchanan's suspension came after the publication of his latest book, "Suicide of a Superpower," which contains a chapter called, "The End of White America." Griffin said last month that he did not think the book belonged in the public discourse and Buchanan has been off the air since October, but news of his suspension did not break until January. At the time, MSNBC said there was no decision yet on his potential future with the network.

In that chapter, Buchanan writes: "Those who believe the rise to power of an Obama rainbow coalition of peoples of color means the whites who helped to engineer it will steer it are deluding themselves. The whites may discover what it is like to ride in the back of the bus."

He adds: "Mexico is moving north. Ethnically, linguistically, and culturally, the verdict of 1848 is being overturned. Will this Mexican nation within a nation advance the goals of the Constitution—to 'insure domestic tranquility' and 'make us a more perfect union'? Or has our passivity in the face of this invasion imperiled our union?"

In another chapter, Buchanan claims that "49 of every 50 muggings and murders in New York are the work of minorities," saying the statistic "might explain why black folks have trouble getting a cab. Every New York cabbie must know the odds, should he pick up a man of color at night."

But it wasn't just his latest book -- Buchanan has long courted racial controversy in his rhetoric. Last April he said that President Obama’s path to the White House was the result of "affirmative action all the way," and in 2009 he asserted that the U.S. "has been a country built, basically, by white folks."

In a brief statement issued Thursday night, the network said simply: "After 10 years, we have decided to part ways with Pat Buchanan. We wish him well."