WASHINGTON – Donald Trump's renewed rhetorical attacks on John McCain are not sitting well with other Republicans – particularly one senator who said he plans to deliver a verbal "whipping" to the president.

Sen. Johnny Isakson, R-Ga., told the website The Bulwark that he plans to give a speech Wednesday on Trump's criticisms of the late Arizona senator, who was the GOP presidential nominee in 2008.

“I just want to lay it on the line, that the country deserves better," Isakson said. "The McCain family deserves better, I don’t care if he’s president of United States, owns all the real estate in New York, or is building the greatest immigration system in the world."

He added: "Nothing is more important than the integrity of the country and those who fought and risked their lives for all of us.”

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When McCain died in August, Isakson said on the floor of the Senate that "anybody who in any way tarnishes the reputation of John McCain deserves a whipping."

Another former Republican presidential nominee, Utah Sen. Mitt Romney, also criticized Trump's tart comments about McCain.

"I can’t understand why the President would, once again, disparage a man as exemplary as my friend John McCain: heroic, courageous, patriotic, honorable, self-effacing, self-sacrificing, empathetic, and driven by duty to family, country, and God," Romney wrote Tuesday on Twitter.

During a series of tweets over the weekend, Trump hit McCain for his handling of a salacious dossier compiled by a former British spy on Trump's relationship with Russia. Court filings unsealed last week detailed McCain's role in the dossier, which set off Trump's criticism of the late senator.

Speaking with reporters on Tuesday, Trump amplified his critique: "I was never a fan of John McCain and I never will be."