McCain declined to accuse Holder of lying, but said there are “significant contradictions” in his testimony.

Lawmakers are probing the DOJ’s seizure of reporters’ emails and phone records in national security leak investigations. 

Holder testified before the committee that he was unaware of any effort to prosecute reporters for publishing leaked information. However, reports claim Holder signed a warrant for Fox News reporter James Rosen’s emails which tagged Rosen as a “criminal co-conspirator.” 

The Justice Department has said that there was never any effort to prosecute Rosen, but House Judiciary Committee Chairman Bob GoodlatteRobert (Bob) William GoodlatteRepublicans fear retribution for joining immigration revolt Immigration petition hits 204 as new Republican signs on GOP centrists threaten to use conservative’s weapon against them MORE (R-Va.) said his panel was “very concerned” that Holder may have lied and had asked him to respond to their questions.

House Oversight Committee Chairman Darrell Issa (R-Calif.) on Sunday warned Holder not to take “perjury lighty.”

McCain suggested that Holder’s effectiveness and authority as attorney general may have been permanently damaged.

“The attorney general has to ask himself the question: ‘Is he really able to effectively serve the president of the United States and the American people under the present circumstances,” said McCain. “That’s a decision he would have to make.”

Holder’s tenure has been marked by frequent clashes with GOP lawmakers, culminating in the vote last year to hold him in contempt of Congress after he refused to turn over documents on a botched gun-walking program.

Asked if Holder should step down, McCain said: “That would be up to him.”

“But I think it would be tough for him to answer the question that he can still effectively serve the president of the United States.”