Both the hard Right, led by Dick Cheney, and the hard Left found cause to be unhappy about Attorney General Eric Holder’s August 24 announcement of a "preliminary review" to determine whether Bush-era interrogations of "specific detainees at overseas locations" violated federal laws.

I’m guardedly betting (and hoping) that the Right’s suspicions that President Obama and Holder are seeking to criminalize policy differences are misplaced, and that in the end the inquiry will infuriate the Left by finding no grounds for new prosecutions, except perhaps of any newly disclosed conduct so egregious as to be indefensible.

I base this speculation mainly on my view that such an anticlimactic result would be the best outcome politically for Obama, and for the country.

Specifically, I doubt that Holder or Obama has any intention of prosecuting such underlings as the CIA agent who strayed beyond Justice Department legal guidance by threatening terrorist mastermind Khalid Shaikh Mohammed with the murder of his children.

I also see no reason to disbelieve Holder’s and Obama’s promises not to go after interrogators who acted "in good faith and within the scope of legal guidance," or to suspect them of targeting the high-level Bush administration officials who approved brutal methods such as waterboarding.

Although Holder was reportedly horrified when he read detailed accounts of brutal interrogations, he must understand that horror cannot justify explosive prosecutions — with little chance of convictions — of honorably motivated public servants.

That’s not to deny the possibility that John Durham, the career Justice Department prosecutor from Connecticut to whom Holder assigned the inquiry, may bring more cases like the one in which a CIA contractor, David Passaro, has already been imprisoned for torturing a detainee to death. But Passaro’s actions were so outrageous that his prosecution was relatively uncontroversial.

If my speculation proves correct, the Left will bitterly accuse Holder and Obama of orchestrating a cynical charade while giving a pass to "war criminals," including former President Bush, Vice President Cheney, and Defense Secretary Donald Rumsfeld.

Meanwhile, some on the Right will complain that Holder and Obama forced patriotic public servants to hire expensive lawyers and put them through investigative double jeopardy to appease (however temporarily) their party’s base and European America-bashers.

Perhaps. But maybe Holder has a better reason for launching this inquiry, even if he expects an anticlimactic denouement. Consider:

• It’s clear that some detainees were put through what international law defines as illegal torture, by both the CIA and the military — and that some were killed. (See my April 4, 2009, column.)

• It’s also clear that the public record puts the United States under an unmistakable obligation to launch a criminal inquiry. In the United Nations Convention Against Torture, the United States and other signatories agreed to make torture by their forces (or others) a grave crime "punishable by appropriate penalties."

• Although the Bush Justice Department and military prosecutors did look into some allegations of extreme torture, there have been few prosecutions, amid hints that some egregious cases may never have been seriously investigated.

• The many centrists as well as liberals here and abroad who see the Bush Justice Department as hopelessly politicized give little credence to Bush-era investigations of torture allegations. These include the work of a task force of career Justice Department prosecutors in Alexandria, Va., who declined to prosecute all but one — Passaro’s — of a reported 10 to 20 cases referred by the CIA’s inspector general and military criminal investigators.

There is undeniable unfairness, which Holder should have acknowledged, in subjecting these same CIA people to a second criminal investigation on top of the administrative discipline already meted out. Still, the severe credibility cloud over the Bush Justice Department argues for taking another look to ensure both the reality and the appearance of justice.

But this logic does not necessarily argue for prosecutions, or even for extensive rehashing of the investigative work already done.

Both Rob Spencer, the former head of the Alexandria task force, and Ken Melson, who oversaw its work and has since been appointed by Holder to a position at Justice, told Newsweek that the cases were "looked at aggressively" by prosecutors who wanted to bring charges if they were warranted and who felt no political pressure to do otherwise.

They were, however, stymied by a lack of witnesses and other evidentiary problems. Also, perhaps, by the narrow congressional definition of illegal "torture"; by the Bush Justice Department’s approval of many brutal methods; by the difficulty of getting juries to convict public servants whose only motive for abusing suspected mass murderers was to save innocent lives; by the substantial evidence that the brutalization of Mohammed and some others may in fact have saved lives; and other factors.

If Durham finds the task force’s no-prosecution decisions reasonable, and uncovers no outrageous new allegations, that should be the end of it — within months, not years. Indeed, in announcing the "preliminary review," Holder noted the possibility that Durham may find too little evidence to call for "a full investigation," let alone prosecutions.

In addition, as National Journal Staff Correspondent Kirk Victor explains on page 48 of this issue, Durham is not (and should not be) a "special prosecutor" with a guarantee of independence from the attorney general — an arrangement that has often led to Javert-like overzealousness. Holder can overrule or fire Durham if he stretches his limited mandate too far.

And Obama can overrule or fire Holder, notwithstanding public suggestions by both men that Holder is completely independent. The Constitution assigns the president — not the attorney general — to "take care that the laws be faithfully executed."

Besides, it’s almost unimaginable that Holder would have launched without his friend Obama’s implicit consent an inquiry that could consume Obama’s presidency if it were to spawn prosecutions of men who at worst crossed lines of legality in their desperation to prevent another 9/11.

How likely is Durham to target, say, those responsible for the most highly publicized interrogation abuses described in a redacted 2004 report, by the CIA’s then-inspector general, that Justice released on August 24?

The former inspector general himself, John Helgerson, has said that "personally, I would not prosecute" anyone for the allegations in his report. They include blowing smoke into detainees’ faces to make them vomit, use of waterboarding more extensive than the Justice Department approved, mock executions, the threat to kill Mohammed’s children, and dramatic threats to execute another Qaeda commander with a gun and a power drill.

Helgerson’s report focused on these methods because Justice had not blessed them in advance. But most seem no more (and perhaps less) torturous than some of the interrogation methods that Justice as well as then-CIA Director George Tenet, Cheney, and perhaps Bush approved: multiple waterboardings, throwing detainees against walls, severe sleep deprivation, and prolonged confinement in a dark box, for example.

In addition, the threats — such as the one about killing Mohammed’s children — did not violate the criminal anti-torture law unless "specifically intended" to cause "prolonged mental harm." That seems most unlikely. These two quoted phrases, which most in the media have ignored, do not come from some Bush Justice Department memo. They come from the anti-torture law itself.

It’s also instructive to compare the above-described conduct with Obama’s own policy of blowing up and burning to death the scores of innocent children, women, and men who are at risk of becoming "collateral damage" when Predator missiles are targeted on homes in Pakistan where Taliban fighters are believed to be hiding.

Indeed, "much of the international law community" has for years been pushing theories that "could make murderers and war criminals out of President Obama or any of the people working for him" on Predator strikes, as detailed by Kenneth Anderson of American University’s law school in a chapter of a forthcoming book edited by Benjamin Wittes. It is posted on the Brookings Institution’s website.

The bottom line is that it would be exceedingly difficult for Holder and Obama to justify going after low-level CIA officials for abusing detainees in ways no more brutal than the methods approved by the high-level officials who will apparently be given a pass as long as they heeded Justice’s legal guidance.

And it would be impossible for Holder and Obama to go after the Bush team — an unprecedented criminalization by one administration of its predecessor’s national security policies — without antagonizing most of the 75 percent of voters who call themselves conservative or moderate.

Such a move would tear the country apart, doom Obama’s ambitious legislative agenda, and possibly make him a one-term president. All for the sake of bringing prosecutions with virtually no chance of convictions.

Surely Holder and Obama understand this. And neither seems inclined to commit political suicide.