MSNBC’s Joe Scarborough wrote about his decision to leave the Republican Party in a Washington Post op-ed published Sunday, calling the GOP a “dying party that [he] can no longer defend.”

In a piece titled “Trump is killing the Republican Party,” the “Morning Joe” co-host called out GOP members of Congress for “shamelessly” standing by President Donald Trump, a “longtime Democrat who switched parties after the promotion of a racist theory about Barack Obama.”

“I did not leave the Republican Party,” he wrote. “The Republican Party left its senses.”

Scarborough announced his decision to leave the GOP last week during an appearance on “The Late Show with Stephen Colbert.”

“I am a Republican, but I’m not going to be a Republican anymore,” Scarborough said. He said he planned to register as an independent voter.

In the op-ed, Scarborough reiterated his belief that the Republican Party abandoned its core values long before Trump became president.

“Neither [Abraham] Lincoln, William Buckley nor Ronald Reagan would recognize this movement,” he wrote.