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.