House Republicans investigating a bungled gun-trafficking probe in Arizona see vindication in a long-awaited watchdog report that criticizes one of their favorite targets: Attorney General Eric Holder's Justice Department. But Justice's inspector general absolved Holder himself of blame.

The department's internal watchdog, Michael Horowitz, will be the only witness Thursday before the House Oversight and Government Reform Committee, a day after he faulted the department for misguided strategies, errors in judgment and management failures in an operation that disregarded public safety and allowed hundreds of guns to reach Mexican drug gangs.

"The inspector general's report confirms findings by Congress' investigation of a near total disregard for public safety in Operation Fast and Furious," said Rep. Darrell Issa, R-Calif., the committee's chairman.

However, committee Republicans will have to tread carefully. The IG's report knocks down some of the many accusations Republicans have made about the Obama administration during their year-and-a-half-long investigation of the operation by the Justice Department's Bureau of Alcohol, Tobacco, Firearms and Explosives. In places, the report reads like a rebuttal of House Republicans' past statements.

"We found no evidence" that staff at the department or at ATF informed the attorney general about Operation Fast and Furious before 2011, the report says.

Former Acting Deputy Attorney General Gary Grindler received a briefing on Operation Fast and Furious in 2010.

"We found, however, that the briefing failed to alert Grindler to problems in the investigation," the report says.

"We found no evidence to suggest" that Assistant Attorney General Lanny Breuer, head of the Justice Department's criminal division, was aware that the ATF and the U.S. Attorney's Office in Arizona had adopted a strategy of not interdicting firearms, the report adds.

Still, the inspector general's report was a form of validation for the Republican-led investigation, saying lower-level officials should have briefed Holder about the investigation much earlier. (MORE)