Among the many voices loudly debating our bombing of Libya this week is one we haven’t heard in a while—the one saying “hey, how much does this cost?” For the first time in many years, costs are part of the national security debate. And despite the political flavor of this particular argument, fiscal responsibility should remain in the fight.

The cost chorus started a few weeks ago with the release of a report by the Center for Strategic and Budgetary Assessments that pegged the price of establishing a no-fly zone over Libya at $30 to $100 million per week. The report pointed out that though cost was only one of many factors that should be considered in such an important national security decision, the current fiscal environment would have to play a role.

Since then, the dollars-and-cents price of our involvement in Libya has become a headline mainstay. News stories track the price of each Tomahawk missile ( $1.4 million each , in case you’re wondering) and lawmakers ask whether the effort’s potential outcomes justify its price tag. Even Good Morning America closed its update on the conflict Thursday with a reference to its estimated cost of $1 billion.

Yes, we know a lot of this talk is born out of pure politicking and peevishness. With the deficit saturating all discussion on Capitol Hill, it's convenient for lawmakers to draw from fiscal arguments—as well as public exhaustion with the wars in Iraq and Afghanistan—when expressing displeasure at being left out of the loop on the decision to engage. But part of the reason for the public’s exhaustion is the fact that those enormously expensive wars were conducted off the accounting books.

Those wars were prosecuted with little attempt to figure out the possible cost ( although we tried ) and funded year-by-year by off budget $150+ billion supplemental appropriations. That’s a chapter of history that must not repeat itself. DOD is currently “cash flowing” funds for the airstrikes, or drawing from existing emergency accounts. This doesn’t mean there won’t soon be a supplemental budget request to cover the costs of the mission, especially considering the price of fuel. Remember that the Pentagon is still operating on the same 2010 budget as the rest of the federal government because of Congresses’ CR dependence.

DOD should not get the kind of blank check they enjoyed during the past decade, however. If our government carefully weighs all the options and decides a mission such as the Libya bombing is a top priority, no problem: That just means a lesser priority will have to go. With a $700+ billion budget—bigger than the combined military budget of the rest of the world—DOD should have no trouble finding a billion or two to cut. And if they do, we have plenty of ideas for them. One immediate option would be to trim defense bill by $4.1 billion in the next CR. That’s how much Congressional earmark funding there was in the FY10 defense budget. Congress trimmed other agencies’ budgets by the value of last year’s earmarks, and defense should not be exempt.

Costs should certainly not dictate national security decisions. But strategic decision-making balances both risk and resources, for failing to account for either will get us into serious trouble. Anyone who says costs have no place in defense decisions should remember that if we bankrupt ourselves with military missions, we won’t be able to buy much of anything in the future.

####

TCS Quote of the Week:

“We know the measures to deal with the long-run deficit are politically difficult. The only way to accomplish them is for members of both parties to accept the political risks together. That is what the Republicans and Democrats on the commission who voted for the bipartisan proposal did. We urge Congress and the president to do the same.”

– Opinion piece by 10 ex-chairs of the President’s Council of Economic Advisors. Politico