Defense Secretary Leon Panetta told lawmakers yesterday he will execute budget cuts “strategically,” while warning additional defense reductions that could come if congressional negotiations fail would amount to “shooting ourselves in the head.”

Panetta and Chairman of the Joint Chiefs of Staff Adm. Michael Mullen struck dire tones in describing what would happen to the military if the new congressional Joint Select Committee on Deficit Reduction and Congress cannot craft a successful plan to cut up to $1.5 trillion in long-term federal spending this year. If the panel can’t agree on a plan that passes the full Congress by Dec. 23, an automatic sequester will slash roughly $600 billion in defense spending over a decade. That’s on top of what the Pentagon says is $450 billion in multi-year reductions mandated in the first wave of spending cuts.

“We’d be shooting ourselves in the head,” Panetta told the Senate Armed Services Committee (SASC) about allowing the sequester to usher in the additional defense cuts.

He “caution(ed) strongly” against such a second wave of military reductions, saying the Pentagon already is “taking on its share of our country’s efforts to achieve fiscal discipline.”

The sequester “is kind of a blind formula that makes cuts all across the board and guarantees that we will hollow out the force,” he said. He pledged to work with lawmakers to ensure “we can meet our national security responsibilities and do our part to help this country get its fiscal house in order but at the same time maintain a strong national defense.”

Mullen said the Pentagon calculates it would be cut by $1.1 trillion if the sequester kicks in. The Defense Department has been saying that the initial $350 billion in long-term defense-related cuts, which the White House initially said would be $330 billion just for the Pentagon, really would be $450 billion over 12 years when compared to budget estimates.

“From my perspective, (a total of $1.1 trillion in cuts) has a good chance of breaking us and putting us in a position to not keep faith with this all-volunteer force that’s fought two wars and that needs to be reset in everything else that we look at for the future,” Mullen said. “And it will impose a heavy penalty on developing equipment for the future….And it will hollow us out. So I think we do need to participate (in the government-wide cuts), and I’ve argued for doing that in roughly the current amount.”

Panetta and Mullen’s concerns were shared by SASC members including Sen. Jeff Sessions (R-Ala.), who also is the ranking member on the Senate Budget Committee.

Panetta maintained the 12-member Joint Select Committee on Deficit Reduction has the “responsibility” to look at the entire federal budget, and not just discretionary accounts such as the Pentagon’s but also entitlement spending.

Panetta said he’s “determined to make these decisions strategically” regarding those currently mandated cuts of $450 billion, and will be “looking at the needs that our Defense Department has to face not just now, but in the future.”

He reiterated for the SASC the guidelines, which he previously described to reporters, that he will use when executing the $450 billion in current Pentagon cuts. Those include maintaining the best military in the world, not “hollowing out the force,” and taking a so-called balanced approach to the reductions.

“I’m going to look at efficiencies, reducing overhead, duplication,” he said. “There are opportunities (to) try to achieve savings, additional savings in those areas. Procurement, looking at the whole process of tightening up on our contracting, creating greater competition with regards to our procurement area.” He also will weigh military compensation.

He pledged, to the receptive audience on the SASC, to not “take the simply way out” and reduce every part of the defense budget by a set percentage. In the past such cuts resulted in a weakened force lacking weaponry, equipment, and training, he said.

“My approach is to look at key areas here and make some tough decisions with regards to savings,” he said.