Less than a week after ’fessing up that it found some 2,500 documents potentially showing that the IRS shared taxpayer returns with the White House, the Obama administration has reversed course and won’t release the trove to a group suing for access.

In an abrupt decision, the Treasury inspector general’s office said that the documents are covered by privacy and disclosure laws and can’t be provided to Cause of Action, despite a promise last week to hand over some 2,500.

The decision coincides with publication by the Washington Examiner this week of "Watchdogs, lapdogs and attack dogs," a four-part series examining the successes and failures of the inspectors-general system, including multiple instances in which IGs provided cover for agency managers seeking to avoid more rigorous evaluations.

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“All of the 2,043 pages of documents we have determined to be responsive were collected by the Secretary of the Treasury with respect to the determination of possible liability under Title 26 of the United States Code. These pages consist of return information protected by 26 U.S.C. § 6103 and may not be disclosed absent an express statutory exception,” said the office in a letter dated Dec. 1.

What's more, Treasury, which oversees the IRS, is still considering what to do with another 466 documents and said that they will provide a "response regarding" them.

Dan Epstein, executive director of Cause of Action, said Treasury was using “sophisticated” lawyering to weasel out of providing the documents. And he noted that their letter said that Treasury Secretary Jack Lew is now looking into “potential liability” that his tax aides broke laws in sharing taxpayer information with the White House.

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Epstein said that either Treasury was “stonewalling” his group, or that Lew “is incompetent” for just now looking at potential lawbreaking by his team on the case that is two years old.

It is just the latest twist in the taxpayer advocate’s effort to prove allegations of political harassment of conservative taxpayers and groups. The documents are not related to the larger IRS harassment of Tea Party groups, but could show a pattern of targeting by the White House.

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Cause of Action had won a Freedom of Information legal action to gain access to the documents and expected them to be redacted. Epstein said that he expects to fight Treasury's move in court.

Paul Bedard, the Washington Examiner's "Washington Secrets" columnist, can be contacted at pbedard@washingtonexaminer.com.