Last year 27 cents of every income tax dollar in the United States went to the military. Even so, that proportion has not generated enough revenue to pay for the military’s operations over the last 13 years, which, in a historic departure, have been funded largely by borrowing.

According to data compiled by the National Priorities Project, US taxpayers spend $10.54 million every hour to pay for the “overseas contingency operations” -- military-speak for undeclared wars -- in Afghanistan and Iraq. Over 96 percent of this figure can be attributed to Afghanistan alone. And these mind-boggling amounts do not include the costs of unofficial undeclared wars, such as the drone strike campaigns in Pakistan, Yemen and Somalia.

The official cost calculations also ignore the ripple effect of 13 years of war on spending by the military, the intelligence services and the Department of Homeland Security. Projections based on federal appropriations before September 2001 suggest that the base budget of the Department of Defense -- the operating costs aside from war -- has ballooned by over $700 billion since the declaration of the war on terror.

Even if the wars were to end tomorrow, the cost of caring for veterans, a segment of discretionary spending separate from other military appropriations, will not peak until at least 30 years from now. In 2010, the Congressional Budget Office (CBO) estimated that the cost of care for veterans of current wars would total $40 billion by 2020, at the low end. The CBO’s cost scenario assumed that the US would reduce the number of troops deployed for war to 30,000 by 2013. More than 39,000 troops are still stationed in southwest Asia and Korea, and it is still unclear whether (or how many) troops will leave Afghanistan before the end of the year. There are already more than 600,000 permanently disabled veterans of the Iraq and Afghanistan campaigns who receive medical care and disability payments.

Tallying the costs of war for US taxpayers -- even tracing the effects of war and deficit spending on mortgage interest rates, lost investment in infrastructure and future interest payments -- offers only a partial and hazy view of the larger picture. The human cost for veterans and their families; for the millions of Afghans and Iraqis either displaced or trying to rebuild their broken, poisoned countries; for a world subject to an ever-expanding regime of overt and covert surveillance -- these costs resist being fit onto a balance sheet.

Accounting for war is a near impossible task. Much more difficult, it seems, than paying for it.