A major Senate probe of the CIA's interrogation and detention practices was seriously derailed Friday when Sen. Kit Bond, the ranking GOP member of the Senate intelligence committee, revealed in a statement that he had pulled the entire GOP staff out of the investigation. Bond blames the move on Attorney General Eric Holder's recent decision to launch a separate criminal inquiry into the agency's abuse of detainees. The move appears to be part of a broader campaign by congressional Republicans and the U.S. intelligence community to pressure Holder to rescind his recent appointment of a special counsel to investigate allegations of torture during the Bush administration.

Bond contends that the intelligence-committee investigation had effectively become pointless, and the panel was "spinning our wheels" because current and former agency officials will now refuse to cooperate with any congressional probe when they face potential prosecution by the Justice Department. "DOJ sent a loud and clear message that previous decisions to decline prosecution mean nothing, and old criminal charges can be brought any time against anyone," Bond said. "Against these odds, what current or former CIA employee would be willing to gamble his freedom by answering the committee's questions?"

But Sen. Dianne Feinstein, the committee's Democratic chairman, insisted the probe will continue regardless. Saying "I very much regret" the GOP's decision, Feinstein added that her probe "is being pursued, additional staff are being hired, and the committee is continuing the work with all due diligence."

The flare-up is significant because, whatever the results of Holder's criminal probe, the Senate panel's investigation offered perhaps the only opportunity for a full public accounting of the U.S. intelligence community's conduct in the aftermath of September 11 attacks. The panel has been granted access to millions of pages of internal CIA documents, almost all of them still classified, and has been conducting interviews with current and former agency officials in order to produce an exhaustive report on the agency's interrogations and detention policy, examining—among other issues—whether the agency's methods had been effective in producing valuable information that had helped thwart terror attacks.

Feinstein's aides have said they had hoped to produce a declassified—and bipartisan—public report by next year. But the withdrawal of the Republican staff is likely, at a minimum, to set the panel's timetable back and embolden resistance to cooperating with the probe among lawyers representing CIA officers. That resistance was already an obstacle and is now likely to intensify. "The pendency of a criminal investigation by the Department of Justice will certainly deter individuals from cooperating with committees of Congress," said Robert Bennett, the renowned Washington criminal-defense lawyer who represents the former chief of the CIA counterterrorism center.

The blowup also underscores how the entire torture issue—including whether CIA operatives and contractors had violated the law when they waterboarded and engaged in other "enhanced"  interrogation techniques—has become hopelessly politicized.

Egged on by former vice president Dick Cheney, Bond and other congressional Republicans have repeatedly attacked Holder for suggesting that anybody in the Bush administration or the U.S. intelligence community might have engaged in illegal conduct when, as they see it, they had simply been protecting the country.

Those arguments have also been advanced by seven former CIA directors who last week sent an extraordinary letter to President Obama asking him to overrule Holder and halt the criminal probe of agency operatives. A senior administration official derided the letter this week, saying that Holder had no intention of backing down because former CIA directors (some of whom could likely become key fact witnesses in any criminal probe) were lobbying the White House to intervene in a criminal investigation.

A spokesman for Holder did not immediately return calls for comment from NEWSWEEK.