Republicans are lashing out at former White House strategist Steve Bannon after the party's stunning election loss in Alabama.
A New York congressman urged the party to "dump" Mr Bannon, saying: "His act is tired, inane and morally vacuous."
The Breitbart News chief is blamed for egging on President Donald Trump to back Roy Moore, who lost on Tuesday.
Analysts say the president is a reactive politician who relies increasingly on the eyes and ears of allies such as Mr Bannon.
'War on the establishment'
The former strategist vowed in October to challenge "every Republican incumbent".
He was a passionate supporter of Mr Moore, an ultra-conservative former judge who crashed to defeat in Republicans' first loss in Alabama in 25 years.
But despite all the criticism, Mr Bannon is defiant.
An unnamed source close to him told Bloomberg: "This doesn't stop Steve's war against the establishment.
"All it does is pour gasoline on top of it."
New York Representative Pete King launched a highly personal attack on Mr Bannon on Wednesday morning.
The Republican congressman tweeted: "After Alabama disaster GOP [the Republican party] must do right thing and DUMP Steve Bannon."
He added: "If we are to Make America Great Again for all Americans, Bannon must go! And go NOW!!"
Mr King later appeared on CNN to say the former Trump adviser "looks like some kind of dishevelled drunk that wandered onto the political stage", even though Mr Bannon reportedly abstains from alcohol.
The congressman also attacked Mr Bannon's "weird alt-right views", which he said did not represent conservative values.
After Alabama disaster GOP must do right thing and DUMP Steve Bannon. His act is tired, inane and morally vacuous. If we are to Make America Great Again for all Americans, Bannon must go! And go NOW!!— Rep. Pete King (@RepPeteKing) December 13, 2017
He added that he blames the election loss in Alabama on voters' "revulsion" towards Mr Bannon.
Illinois Republican Adam Kinzinger referred to Mr Bannon as a "RINO", a derogatory term meaning Republican in name only.
"His morally inept strategies are unwelcome here. #YoureFired," Mr Kinzinger tweeted.
Steve Law, president of the Senate Leadership Fund, a political group aligned with Senate Majority Leader Mitch McConnell, piled in, too.
"Not only did Steve Bannon cost us a critical Senate seat in one of the most Republican states in the country, but he also dragged the president of the United States into his fiasco," he said in a statement.
"This is a brutal reminder that candidate quality matters regardless of where you are running."
Bannon is a RINO. His morally inept strategies are unwelcome here. #YoureFired— Adam Kinzinger (@RepKinzinger) December 13, 2017
Mr Bannon has recently set his targets on Mr McConnell, whom he views as lukewarm on the president's so-called America First strategy.
The editorial board of the National Review, a conservative magazine, called Mr Bannon a "cut-rate Svengali... who never met a disreputable political candidate he didn't like".
The former Trump strategist was widely credited with honing Mr Trump's populist appeal in last year's election campaign.
Mr Bannon left the White House in August to help Mr Trump's administration as "a wingman outside" by returning to his role as head of right-wing Breitbart News, he said.
But in Alabama's Republican primary election he backed ultraconservative former judge Roy Moore, finding himself at odds with his former boss.
Mr Trump had backed a mainstream Republican, Luther Strange, who lost.
Some in Washington began to see Mr Bannon as a potential "king-maker" for the party.
Mr Trump later endorsed Mr Moore during his contest against Democrat Doug Jones, who won by a razor thin margin on Tuesday night.
The Washington Post reported that Mr Trump made his decision after a long discussion with his former aide.