Updated: 6:55 p.m.

The Department of Justice, following longstanding practice by prior administrations, is declining to prosecute Attorney General Eric Holder for being in contempt of Congress, Deputy Attorney General James Cole said Thursday in a letter to Speaker John Boehner (R-Ohio).

Along with the contempt citation, House Republicans passed a resolution Thursday granting authority to bring a civil suit to enforce the contempt resolution.

“Across administrations of both political parties, the longstanding position of the Department of Justice has been and remains that we will not prosecute an Executive Branch official under the contempt of Congress statute for withholding subpoenaed documents pursuant to a presidential assertion of executive privilege,” Cole wrote.

In response, Republicans noted that they had not yet transmitted the contempt proceeding to the U.S. Attorney for the District of Columbia, whom federal law accords the authority to determine whether to prosecute.

That official, Ronald Machen, Jr., was recently named by Holder as one of two U.S. attorneys to lead a separate investigation into national security leaks.

Sen. Chuck Grassley (R-Iowa) sent a response letter to Machen questioning Cole’s letter.

“The law clearly assigns that duty to you and to no one else. It could have assigned the duty to the Attorney General or to the Deputy Attorney General or some other official. But, it does not,” Grassley wrote.

He suggested that how Machen and the DOJ handled the contempt citation may show that Machen is not sufficiently independent to head the leaks probe either.

“Your independence and integrity were cited as the reason that there was supposedly no necessity to appoint a special prosecutor [into the leaks],” Grassley wrote. “This matter gives you an opportunity to live up to that high praise and prove your independence. However, the way this has been handled so far suggests no such independence at all. Before you have even received the citation, before you have even had a chance to understand the scope of the documents and the privilege claim at issue, the Deputy Attorney General has already announced the decision of ‘the Department’ not to proceed as required by the contempt statute.”

Grassley Machen to respond to several questions, including whether he has talked to Cole about the contempt citation or the “Fast and Furious” operation, if he had been instructed to not present the citation to a grand jury and if he has independently reviewed the case.

Grassley asked for a response by Tuesday.

In remarks to reporters, White House Press Secretary Jay Carney noted that the practice of declining to prosecute contempt citations on administration officials dates back to the Reagan administration.

Carney also slammed Republicans for holding Holder in contempt, saying House Oversight and Government Reform Chairman Darrell Issa (R-Calif.) had gone even further than Rep. Dan Burton (R-Ind.) had when he chaired the panel during the Clinton administration.

“I covered Congress back in the ’90s when the chairman of that same committee, I think as I recall correctly, managed to pass — when the Republicans controlled Congress … a vote of contempt of the attorney general just through the committee of Janet Reno. And then Speaker Newt Gingrich, who was, I think we can all agree, not a political friend of the President of the United States at the time, refused to have that vote come to the floor,” Carney said according to a pool report.

Carney said Holder will “continue his excellent work as Attorney General of the United States.”

Separately, Grassley wrote DOJ Inspector General Michael Horowitz regarding alleged instances of whistleblower retaliation.

That letter says two of the main Fast and Furious whistleblowers have been placed under the supervision of an official who threatened to retaliate against them for blowing the whistle.

According to the letter the official, Scot Thomasson, said the Bureau of Alcohol, Tobacco, Firearms and Explosives needed to “take [the whistleblowers] down.”

“All these whistleblowers have axes to grind. ATF needs to f–k these guys,” Thomasson said according to the letter.

Grassley asked whether Thomasson had been admonished and what steps had been taken to ensure he did not retaliate against the officials now under his supervision.