WASHINGTON, June 5 - Disparate inquiries into abuses of prisoners in Iraq and Afghanistan have so far left crucial questions of policy and operations unexamined, according to lawmakers from both parties and outside military experts, who say that the accountability of senior officers and Pentagon officials may remain unanswered as a result.
No investigation completely independent of the Pentagon exists to determine what led to the abuses at Abu Ghraib prison, and so far there has been no groundswell in Congress or elsewhere to create one.
But on Capitol Hill, even some Republicans have begun to question whether the Pentagon's inquiries are too narrowly structured to establish the causes of the abuses, as Defense Secretary Donald H. Rumsfeld and others have pledged to do, and then to determine if anyone in the chain of command was responsible for them.
Some House Republicans, bucking their leaders who have said the focus on Abu Ghraib is distracting from the larger effort in Iraq, have joined Democrats in urging a more aggressive review of the investigations. In the Senate, members of both parties said there remained major aspects that fell outside the scope of any of the investigations that are under way - including the role of military lawyers in drafting policy on detainees and the involvement of civilian contractors in their interrogations.
Senator Lindsay O. Graham, Republican of South Carolina, said he was troubled that the only criminal cases brought so far involved seven low-ranking soldiers from the 372nd Military Police Company. He said he believed that there was "command failure at many levels that could be criminally culpable."
Representative Heather Wilson, a New Mexico Republican and former Air Force officer, was unsparing in her assessment of the House's investigative oversight role to date: "We should be doing this directly and bluntly, and in the House we are not. It's been very disappointing to me."
The top military spokesman in Iraq, Brig. Gen. Mark Kimmitt, this week defended the range and scope of the various military investigations. "We're going to go wide, we're going to go deep, we're going to look under every rock and find out just how far this went," he said.
Dozens of criminal investigations into accusations of abuses against prisoners have yet to be resolved, and some may never be, officials concede. Additional criminal cases stemming from the abuses at Abu Ghraib appear to have been put on hold while a separate investigation is completed into the role military intelligence soldiers may have played there and at other prisons in Iraq - an inquiry whose findings have been delayed at least until July.
In addition to the criminal cases, which have included investigations into the deaths of at least 40 prisoners in Iraq and Afghanistan, the Pentagon has ordered six inquiries or reviews since a soldier came forward in January with evidence of the Abu Ghraib abuses. Two have been completed. The others have narrow focus and limited scope; while in theory they could recommend criminal charges, that is not their focus.
Mr. Rumsfeld, facing criticism over his leadership and calls from some Democrats to resign, last month appointed a four-member panel, led by James R. Schlesinger, a former defense secretary, to assess whether the inquiries are sufficient. That has led some to push for broader inquiries under various authorities, possibly a select committee in Congress, a military court of inquiry, or a panel like the one created to investigate the Sept. 11, 2001, attacks.
The commission plans to begin interviews on June 14 at the Pentagon and by teleconference with officers in Iraq. It is building a staff of 25, including several military lawyers on loan from the Pentagon.
One of its members, Tillie K. Fowler, a former Republican congresswoman from Florida, said the commission intended to do a wide assessment, and would probably interview senior military officers, including Lt. Gen. Ricardo S. Sanchez, the ground commander in Iraq. But she also made it clear that Mr. Rumsfeld was not a focus.