MT. VERNON — Republicans, and many Democrats, are upset by the prospect of so-called sequestration cuts to the nation’s defense budget. Pentagon chief Leon Panetta is so alarmed that the day before the Senate took up what became the “fiscal cliff” agreement, he called a key Republican lawmaker, Sen. Lindsey Graham, to express deep concern that the cuts might go into effect. As it turned out, Congress put them off for two months.

Sequestration would force the government to reduce discretionary spending by about $1.2 trillion over the next decade. Roughly half of that, or $600 billion, would come from defense – a hugely disproportionate amount to take from the Pentagon. And the cuts would be the worst possible sort: everything slashed, across the board, good programs and bad.

That’s no accident. Sequestration was designed to be so awful that Congress would find a better way to cut spending. So far, that hasn’t happened.

But just because the sequestration cuts are bad doesn’t mean the defense budget should be sacrosanct. In fact, there are hundreds of billions of dollars in Pentagon spending that can be cut without compromising the military’s effectiveness.

Maintaining national security requires underwriting a lot of departments: Defense, Homeland Security, Veterans Affairs and countless others.

But looking just at the Defense Department, the Obama administration this year plans to spend (without sequestration) $550 billion on the basic operations of the Pentagon, plus $88 billion specifically on the war in Afghanistan – a total of $638 billion.

Back in 2007, the Pentagon’s base budget was just $431 billion, with $132 billion added for the war in Iraq and $34 billion for Afghanistan – a total of $597 billion. Given that it was a peak year for war spending in Iraq, in part because of a costly troop surge, is there any reason the U.S. should be spending more on the Pentagon’s base budget today, adjusted for inflation, than it did in 2007?

“If we go back to ‘07, we had the Army we have today, and it was surging in Iraq, with all the logistical support it needed,” says one senior GOP Senate aide. “No one in ‘07 was screaming that we didn’t have enough money for the military.”

How to get back to those 2007 levels? Watchdog groups, along with Republican Tom Coburn, the Senate’s leading budget hawk, have plenty of suggestions.

For example, the Pentagon is building several versions of the F-35 fighter plane. Models specific for the Navy and the Marines have been “plagued by cost overruns and schedule delays, and are now estimated to cost just under $200 million each,” according to a report by Taxpayers for Common Sense and the Project on Government Oversight. Replacing the two extra models of the basic F-35 with the F/A-18 fighter – ending up with the same total number of planes, but a combination of F-35s and F/A-18s – could save about $61 billion over the next decade.

Then there is health care. Coburn wants TRICARE, the military health care system, to require greater out-of-pocket payments from retired soldiers who were not in any way disabled by their service and are not yet eligible for Medicare. Their out-of-pocket expenses have been basically unchanged since 1995, while health care costs have risen dramatically. Making that change and a few others in TRICARE, Coburn estimates, could save more than $180 billion in the next decade.

Then there is outside services contracting, a practice that has nearly tripled in cost since 2000. Former Defense Secretary Robert Gates tried to slow it down, and there are measures in place to freeze it.

But Coburn points out that “reducing Department of Defense spending on service contracts by 15 percent over the next 10 years would still leave contract spending at approximately the level it was in 2007, when the U.S. was fighting in Iraq and Afghanistan.” Doing so would save an estimated $370 billion over the next 10 years.

There are many other possible savings. The long-troubled Osprey tilt-rotor plane is still a problem; it could be mostly replaced by helicopters, for a saving of $17 billion.

An additional $9 billion could be saved by ending the Pentagon practice of running its own domestic grocery stores. And so on.

In all, Coburn envisions a possible $1 trillion in cuts over the next decade. Others see cuts in the $600 billion range.

In any event, it’s big money. Whatever the figure, the bottom line is that Republicans decrying the sequestration cuts should remember the Pentagon budget still needs to be reduced – just in the right way.