Amid the fog surrounding the recently enacted Budget Control Act and the new Joint Select “super” Committee on Deficit Reduction, one thing is clear: National defense spending has been taken hostage. Policymakers from both parties think threatening draconian defense cuts can protect their positions on taxes and entitlement spending.

Put simply, the deal is a setup to cut defense. The only questions for the deal makers are how much and by what means.

The cuts will come in two stages. First up, the discretionary spending caps already legislated for fiscal 2012 through 2021. Office of Management and Budget Director Jack Lew estimates they’ll slash roughly $350 billion from defense over 10 years. The second step could involve a “sequester” to reduce discretionary spending an additional $1.2 trillion in fiscal 2013 through 2021 - half of that coming specifically from defense. Combined, these two steps could take nearly $1 trillion from national security spending. That would be devastating.

Here’s how the second step likely will work.

The Joint Select Committee has until late December to agree on a plan to save $1.2 trillion and Congress until Jan. 15 to enact it into legislation. Failure to do so automatically triggers the sequester mechanism. President Obama would then issue a sequester order to reduce the major defense accounts - including operations, procurement, personnel costs and research and development - by “a uniform percentage” starting Jan. 2, 2013.

The prospective “trillion-dollar haircut” for defense would constitute a scalping, so there will be enormous pressure for a “compromise” on taxes and entitlements to “save defense.” In essence, the threat of gutting national security enables Democrats to say Republicans would sooner sacrifice security than raise taxes, and Republicans can say Democrats would rather scuttle defense than rein in burgeoning entitlements.

Here’s the rub: The deal approved by Congress takes only one hostage: national security spending. Some entitlement spending would be hit with a sequester, but all concerned know those programs must somehow be cut. Taxes and most other entitlement spending get a pass. No crocodile tears from lawmakers over the “trigger” can cloud the facts. They’ll argue it’s far better to manage defense cuts through a regular congressional process than through ham-fisted, across-the-board reductions. They’ll wrap themselves in the mantle of “saving defense” even as they rob its budget.

Make no mistake, how much to cut from defense is more important than the means by which it’s imposed. The sky’s the limit.

Some will say it’s better to cut $800 billion or so over 10 years than suffer the full trillion in cuts via the two-step process. The vice president is said to be floating taking another $800 billion to $850 billion from defense over 10 years through a combination of the two steps. So dropping defense by “only,” say, $600 billion in the sequester step can be billed as a grand compromise.

Here’s the problem: Military experts warn that cuts of this scope will fundamentally alter American military power. They will force reductions in forces and weapons that cannot be recovered easily. Fewer capabilities could require fundamentally changing military strategy. We’ll be asking our men and women in uniform, even those deployed in harm’s way, to get by with far less.

Defense already has absorbed massive reductions in spending. Vital programs and technological advances have been chopped by nearly $500 billion just over these past two years. It’s hard to imagine absorbing even that much again without irrevocably harming national security. The impact on our armed forces will be unsustainable and irreversible except at great cost.

Next year, Congress should go back to the drawing board before accepting forced defense cuts. Congress should press for discretionary spending cuts as required in the new budget law but exclude defense spending from any across-the-board cutting. The second round of cuts doesn’t have to go into effect until January 2013, leaving Congress an entire year to figure out how to undo the mess it got America into - cutting spending to be sure, but leaving defense spending at levels commensurate with the nation’s external threats.

Kim R. Holmes, a former assistant secretary of state, is a vice president at the Heritage Foundation.