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.

Read the op-ed in its entirety here.

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President Donald Trump kisses First Lady Melania Trump after disembarking form Air Force One upon arrival at Paris Orly airport on July 13, 2017, beginning a 24-hour trip that coincides with France's national day and the 100th anniversary of US involvement in World War I. Donald Trump arrived in Paris for a presidential visit filled with Bastille Day pomp and which the White House hopes will offer respite from rolling scandal backing home.

A woman holds a placard in support of Trump as he arrives in Paris.

First Lady Melania Trump speaks with children as she visits Necker Hospital for children on July 13, 2017 in Paris, France.

French President Emmanuel Macron, right, welcomes First Lady Melania Trump while his wife Brigitte Macron President Trump outside the Army Museum during a ceremony at Les Invalides in Paris, on July 13, 2017.

Trump and French President Emmanuel Macron stand during the US and French national anthems.

Trump is welcomed by French President Emmanuel Macron during a welcome ceremony at Les Invalides in Paris.

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Macron and Trump talk during the welcome ceremony.

Trump, First lady Melania Trump, French President Emmanuel Macron, and his wife Brigitte Macron listen to the Director of the Army Museum, David Guillet, as they visit Napoleon Bonapartes tomb at Les Invalides in Paris, on July 13, 2017.

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This article originally appeared on HuffPost.