A specter is haunting the Pentagon: the prospect of Leon Panetta, the newly nominated Secretary of Defense, gleefully wielding his budget axe, slashing his way through the 5-sided building.

CIA director Panetta has worn many hats in his hugely multifaceted Washington career –a one-time moderate Republican congressional aide, former head of the office of civil rights under Richard Nixon, assistant to former Mayor John Lindsay of New York, an eight-term Democratic Congressman from California, head of the House budget committee, Bill Clinton’s chief of staff and first budget director, and Team Obama national security insider. But officials say it was Mr. Panetta’s role as a happy budget warrior that most attracted President Obama.

“Leon will know how to cut the bloated defense budget,” said Richard Clarke, the former counter-terrorism and cyber-terrorism White House adviser under presidents Clinton and Bush.

Given the public’s growing concern about the nation’s burgeoning debt and deficit spending, budget reductions now rank high on President Obama’s security agenda.

In explaining Obama’s selection to reporters at a press background briefing yesterday, one official specifically mentioned the $400 billion in security-related cuts that the president wants to make over the next 12 years. “Director Panetta’s experience as a manager and a manager of very large budgets, someone who is familiar with large organizations and has the ability to lead those organizations and implement strategy in those organizations, is a real strength that he brings here,” the official said, according to an account in Politico.

Some say that cuts could be almost double that sum -- across-the board reductions that Secretary Bob Gates has staunchly resisted. Mr. Gates has warned that such reductions may endanger readiness and the military’s ability to carry out its many wars and commitments abroad.

By most accounts, Leon Panetta had to be talked into taking the top Pentagon job. Hillary Clinton was said to have been the leading candidate to replace Gates, who is leaving in July, until she indicated in no uncertain terms that she did not want the job.

The default inside favorite then became Mr. Panetta, who has successfully guided the CIA through tough challenges for over two years. By all accounts, he liked the CIA job and was reluctant to leave. Friends say he was looking forward to spending even more time with his wife and family at their walnut farm in Carmel Valley, California. With no shortage of hobbies and interests, Panetta, who turns 73 this June, was not seeking another post until President Obama pressed him to head the Pentagon, which he agreed to on Monday night.

Thanks to his previous jobs, Panetta “knows the Obama administration’s centralized command structure, knows the Hill, and knows the defense budget,” said Les Gelb, a leading national security expert who ran the Council on Foreign Relations and now writes for the Daily Beast. “He was the best available Democrat for the job.”

Dov Zakheim, a former undersecretary of defense and Pentagon comptroller under President Bush, said he thought that it was not only Panetta’s budget-cutting expertise that made him a natural for the post. “The White House wanted someone it could absolutely trust, someone with name recognition, and above all, someone who would not make waves over policy, for example, on Libya, as Sec. Gates did,” he said. “So he fit the White House bill perfectly.”

Senator Jack Reed, Democrat of Rhode Island, who was once considered for the job given his expertise in defense and closeness to the president, but was not interested in leaving the Senate, called Panetta an “extraordinarily talented individual” who had taken command of the CIA “at a difficult moment.” As controversies over abusive interrogation techniques and other alleged CIA practices swirled, Panetta had done “exceptionally well,” the senator said, “improving morale at the agency."

But it is the budget-cutting mandate not only for DOD but for all of national security that most worries Senator Reed and other veteran senators with expertise in foreign affairs. Though aware of the need to cut Pentagon waste and excess, he expressed concern that excessive budget trimming might come at the expense of the “pro-active diplomatic assistance” that is vital to achieving and consolidating military victories. “We saw what happened in Afghanistan with ‘Charlie Wilson’s War’,” he said, referring to the book by the late George Crile about how America helped push the Soviets out of the Afghanistan but subsequently abandoned the field to Islamic militants. “If we cut aid to Iraq and Afghanistan and walk away again,” he said, “we risk sacrificing hard-won military achievements.”

Judith Miller is a writer, Manhattan Institute scholar and Fox News contributor. She appears as a panelist this weekend on "Fox News Watch" Saturday, April 30 at 2:30 p.m. ET.