For the sake of national security and national unity, President-elect Barack Obama should put a stop to efforts to investigate or prosecute Bush administration officials for anti-terror “war crimes.”

The motive behind such efforts is not — as claimed — “truth” or “justice,” but political vengeance.

Republicans hated President Clinton and a GOP House impeached him. Many Democrats hate George W. Bush with equal or even greater passion, but they demurred on the idea of impeachment — mainly because the action against Clinton hurt the GOP more than it hurt Clinton.

But now Bush haters are calling for the Obama administration to investigate Bush officials for alleged war crimes and other misdeeds connected with the war on terror.

Obama should make it clear right now that he opposes such action — and also that he opposes the “compromise” idea of a “truth commission” to investigate alleged Bush-era wrongdoing.

The main reason has less to do with “turning the page,” uniting the country and letting bygones be bygones — all good Obama impulses — than with preserving the morale of intelligence professionals in wartime.

If a special prosecutor were to be appointed to investigate possible criminality involved in detainee interrogations, “extraordinary renditions” or terrorist surveillance, it’s not only Bush-era top officials who’d have to hire lawyers to defend themselves, but lower-down intelligence operatives as well.

The same would be true if Congress created a “truth commission” with subpoena power to report on Bush-era policies. The operatives wouldn’t have to fear prosecution, but they’d still have to worry about their reputations.

And, when President Obama calls on the CIA to undertake a dangerous mission — perhaps a terrorist “snatch” in the tribal areas of Pakistan or the assassination of Osama bin Laden — any agent directed to undertake it would justifiably demand a legal opinion first.

And CIA lawyers, too, would err on the side of caution to avoid future second-guessing.

The latest call for a punitive action came from the New York Times editorial page on Dec. 18, but it’s previously been by left-wing bloggers, liberal Rep. Jerrold Nadler (D-N.Y.) and commentators on MSNBC.

The take-off point for the Times was a Senate Armed Services Committee’s bipartisan finding that high-level authorization of “aggressive” interrogation of terrorist detainees led to abuses such as those perpetrated at Iraq’s Abu Ghraib prison.

The report, the Times wrote, “amounts to a strong case for bringing criminal charges against former Defense Secretary Donald Rumsfeld; his legal counsel, William Haynes; and potentially other top officials, including former White House counsel Alberto Gonzales and David Addington, Vice President Cheney’s former chief of staff.”

I’m surprised that the newspaper did not call — as others have — for prosecution of Cheney himself, and possibly Bush as well.

After all, among the committee’s conclusions was that “On Feb. 7, 2002, Bush made a written determination that Common Article 3 of the Geneva Conventions, which would have afforded minimum standards for human treatment, did not apply to al-Qaida or Taliban detainees.

“Following the president’s determination, techniques such as waterboarding, nudity and stress positions, used in (U.S.) training to simulate tactics used by enemies that refuse to follow the Geneva Conventions, were authorized for use in interrogations of detainees in U.S. custody.”

But there’s no need to investigate whether Bush — or Cheney — authorized the use of “enhanced” interrogation techniques or warrantless terrorist wiretapping or renditions (“snatching”) of terrorist suspects.

They’ve admitted it and defended it as being necessary to defend the nation in the aftermath of the Sept. 11, 2001, attacks — and justified it by pointing out that the homeland has not been attacked since.

In an interview with the Washington Times on Dec. 17, Cheney said “there were a total of about 33 (persons) who were subjected to enhanced interrogation. Only three of those who were subjected to waterboarding,” including 9/11’s top planner, Khalid Shaikh Muhammad.

Intelligence officials claim that his subjection to simulated drowning produced important information about the al-Qaida organization and future plans.

And, they say, the House and Senate Intelligence committees — as well as top Congressional leaders — have been fully briefed about and approved of all major U.S. covert operations, terrorist surveillance and interrogation methods.

What Obama plans to do about proposals for investigation or prosecution of Bush officials remains uncertain.

On one hand, Obama has said that if he found “that there were high officials who knowingly, consciously broke existing laws (and) engaged in cover-ups of those crimes … then I think a basic principle of our Constitution is nobody above the law.”

And Obama’s attorney general designate, Eric Holder, has alleged that top Bush officials “authorized the use of torture, approved of secret electronic surveillance of American citizens, secretly detained American citizens without due process of law … and authorized use of procedures that both violate international law and the U.S. Constitution.”

On the other hand, Obama said on the campaign trail in April that “I would not want my first term consumed by what was perceived on the part of Republicans as a partisan witch hunt, because I think we’ve got too many problems to solve.”

Obama should find an opportunity soon to reiterate that position. If he did so, he could eliminate the unseemly possibility that Bush, on his way out of office, would issue a blanket pardon to everyone in his administration who participated in the war on terror.

The fact is, Obama does have “many problems to solve.” Among them is the possibility raised by a Congressionally mandated commission — that terrorists will use a nuclear or biological weapon somewhere in the world by 2013.

To prevent that catastrophe, Obama might well want to order an “enhanced interrogation,” wiretap a terrorist or even kill one. If he issues the order, he will want someone to carry it out.