The Pentagon is seriously underestimating the financial costs of America’s adventures in Iraq and Afghanistan, which has killed more than 6,000 U.S. soldiers and wounded nearly 100,000, according to a report released ahead of the July 4 weekend from Brown University.

The study received scant media play.

While the Pentagon puts the 2001-2011 war tab at $1.2T, Brown figures that cost is more in the $3.2T to $4T range when tallying outlays for interest, veterans’ care, homeland security and war-related aid to Iraq, Afghanistan and Pakistan.

The Watson Institute researchers note the Iraq and Afghanistan conflicts differ from past wars that were bankrolled by tax hikes and war bonds. The current conflicts are financed almost entirely by borrowing, which in turn raises interest rates and adds to the national debt.

The interest paid on Pentagon spending for the ten-year period is about $185B, according to the report. Brown warns that unless the U.S. immediately repays borrowed money, interest payments would total $1T by 2020.

The researchers report that the Pentagon has spent more than $32B for medical care and disability for veterans of Iraq and Afghanistan. It projects future medical and disability outlays to peak in 30 to 40 years in the range of $600B to $1T.

Brown also measured the “lost jobs” component of waging the two wars. It finds that 8.3 jobs are created for every $1M spent by the military for weapons and supplies.

According to Brown: “Military spending presents a much bigger leakage to the economy, as military personnel spend more of their earnings abroad and more equipment and materials are procured from outside the U.S….While these funds did indeed create jobs in the military and related sectors, the opportunity cost of this spending is the additional jobs that would have been created if we had spend these funds on other domestic programs.”

The Pentagon’s annual $130B budget for Iraq, Afghanistan could have supported 300K construction jobs or 780K in healthcare or 900K in education.

President Obama promises to remove 33K troops, which is the number of the “surge” forces by the end of next year. He should bring the other 70K soldiers home as soon as possible. We’ve shed enough blood and treasure there. And we will be footing the bill for quite some time.