Panetta’s new target may be even more elusive than was bin Laden. As secretary of defense, his top concern is finding ways to cut the Pentagon budget that don’t gut the U.S. military. The biggest danger is that Congress will insist on protecting pet weapons projects, forcing Panetta to cope with the budget squeeze by reducing troops and “hollowing out” the structure of U.S. forces.

Panetta can live with the $450 billion reduction in planned defense spending over the next 10 years that was promised by his predecessor, Bob Gates. His nightmare scenario is if the congressional “supercommittee” fails to reach agreement on $1.2 trillion in budget cuts, forcing an across-the board sequestration of funds. Panetta’s aides reckon that would mean a doubling of the cuts in defense, to about $1 trillion.

     If Panetta were forced to those deeper cuts, he fears he would have to make the choices defense secretaries dread most — deciding the relative importance of different deadly threats. Should he stress systems that might be needed to contain China’s rise, or those necessary to project U.S. power in a turbulent Middle East? Should he remain vigilant against a future threat in Asia from North Korea, or spend more on homeland defense? Those are the kind of “Hobson’s Choices” that Panetta fears may be ahead.

      The trickiest aspect about the budget fight is that it can subtly pit a defense secretary against a log-rolling alliance between members of Congress, who want to maintain weapons contracts for their districts, and service chiefs, who want to maintain their own service’s programs and prerogatives. In such moments, notes one former service secretary, “The Navy understands very well who the enemy is — it’s the Air Force.”

      To avoid such internecine sniping, Panetta has been meeting regularly since he arrived at the Pentagon this summer from the CIA. Where Gates frightened the service secretaries into submission, Panetta wants to get to know them, up close and personal, until he understands where the weak links are, and can take action.

    Panetta has the right resume to be defense secretary when a main battlefront will be budget cutting. He was part of the congressional conference that produced the 1985 Gramm-Rudman-Hollings Act, which was supposed to produced balanced budgets but was vitiated by congressional dithering and dereliction. And he was in the Clinton White House during the last GOP budget jihad, under House Speaker Newt Gingrich, when the Republicans, as Panetta remembers it, moved from the politics of obstruction to a decision that “governing is good politics.”

    The new defense secretary realizes that no matter what he does, he’s going to make some people angry — so, given that, he might as well do the right thing. That’s a good rubric for the budget-cutting season that is now enveloping every branch and agency of government in Washington.