Retired Lt. Col. Ralph Peters announced that he was quitting Fox News as a strategic analyst on Tuesday in a fiery email to colleagues, BuzzFeed News reported.
"Over my decade with Fox, I long was proud of the association. Now I am ashamed," Peters wrote.
"Four decades ago, I took an oath as a newly commissioned officer. I swore to 'support and defend the Constitution,' and that oath did not expire when I took off my uniform. Today, I feel that Fox News is assaulting our constitutional order and the rule of law, while fostering corrosive and unjustified paranoia among viewers," he said.
"In my view, Fox has degenerated from providing a legitimate and much-needed outlet for conservative voices to a mere propaganda machine for a destructive and ethically ruinous administration," Peters continued.
The former contributor wrote that he was "appalled" by network hosts who had previously criticized former President Obama for his handling of Russian President Vladimir Putin for now advancing "Putin's agenda by making light of Russian penetration of our elections and the Trump campaign."
He added that his criticisms of Fox News did not apply to sister channel Fox Business, "where numerous hosts retain a respect for facts and maintain a measure of integrity."
"Ralph Peters is entitled to his opinion despite the fact that he's choosing to use it as a weapon in order to gain attention," Fox News said in a statement. "We are extremely proud of our top-rated primetime hosts and all of our opinion programing."
