Harvard Study: Iraq and Afghanistan Wars to Cost Between $4 and $6 Trillion

Most of which has not been paid

The final cost of the Iraq and Afghanistan wars will be between $4 and $6 trillion — and most of those costs have yet to be paid, according to a new study out of Harvard University.

The report from Harvard Kennedy School professor Linda Bilmes finds the Iraq and Afghanistan wars together will be the most expensive in U.S. history when long-term medical and disability costs for service members are factored in.

"The legacy of decisions taken during the Iraq and Afghanistan wars will dominate future federal budgets for decades to come," Bilmes wrote.