WASHINGTON –In a tweet, President Donald Trump responded to Rep. Justin Amash's op-ed announcing that he would leave the Republican Party, calling him "one of the dumbest & most disloyal men in Congress."

"Great news for the Republican Party as one of the dumbest & most disloyal men in Congress is 'quitting' the Party," Trump wrote.

Referencing the field of Republican challengers that had announced they would enter the Republican primary against Amash, Trump added, "Knew he couldn’t get the nomination to run again in the Great State of Michigan. Already being challenged for his seat. A total loser!"

Donald Trump Jr. the president's son, had previously threatened to help support a primary challenge against Amash.

Amash had written an op-ed published Thursday morning explaining that he would be "declaring my independence and leaving the Republican Party." He lashed out at the two-party system, arguing that he was "disenchanted with party politics" and "frightened by what I see from it."

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"The two-party system has evolved into an existential threat to American principles and institutions," Amash continued.

Amash was also the first and only Republican in the House so far to support impeaching Trump. In a Twitter thread published in mid-May, Amash explained that he thought Trump had committed "impeachable conduct" and laid out the case for impeaching Trump. He's also flirted with an independent bid for president in 2020.

Contributing: Ryan Miller

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