The regulations that govern the Army’s relations with the Arroyo Center, the division of RAND that does research for the Army, stipulate that Army officials are to review reports in a timely fashion to ensure that classified information is not released. But the rules also note that the officials are not to “censor” analysis or prevent the dissemination of material critical of the Army.

The report on rebuilding Iraq was part of a seven-volume series by RAND on the lessons learned from the war. Asked why the report has not been published, Timothy Muchmore, a civilian Army official, said it had ventured too far from issues that directly involve the Army.

“After carefully reviewing the findings and recommendations of the thorough RAND assessment, the Army determined that the analysts had in some cases taken a broader perspective on the early planning and operational phases of Operation Iraqi Freedom than desired or chartered by the Army,” Mr. Muchmore said in a statement. “Some of the RAND findings and recommendations were determined to be outside the purview of the Army and therefore of limited value in informing Army policies, programs and priorities.”

Warren Robak, a RAND spokesman, declined to talk about the contents of the study but said the organization favored publication as a matter of general policy.

“RAND always endeavors to publish as much of our research as possible, in either unclassified form or in classified form for those with the proper security clearances,” Mr. Robak said in a statement. "The multivolume series on lessons learned from Operation Iraqi Freedom is no exception. We also, however, have a longstanding practice of not discussing work that has not yet been published."

When RAND researchers began their work, nobody expected it to become a bone of contention with the Army. The idea was to review the lessons learned from the war, as RAND had done with previous conflicts.

The research was formally sponsored by Lt. Gen. James Lovelace, who was then the chief operations officer for the Army and now oversees Army forces in the Middle East, and Lt. Gen. David Melcher, who had responsibility for the Army’s development and works now on budget issues.