The true price of U.S. military operations abroad has far outstripped early projections and continues to climb, largely because they have been financed through borrowing rather than direct funding, Bloomberg reports.

The Iraq war stands as one of the clearest examples. In 2003, the administration of then-President George Bush estimated that toppling Saddam Hussein would cost about $50 billion. Subsequent assessments told a starkly different story, with the final bill rising many times over the original forecast.

Harvard University professor Linda Bilmes calculates that total U.S. spending on the Iraq campaign has reached roughly $4.5 trillion. A substantial share of that sum, she notes, was covered by expanding the national debt. Bilmes argues that the United States has shifted from being a country preoccupied with paying for wars upfront to one that relies on emergency funding and borrowing — effectively charging military campaigns to what she describes as a national credit card.

Economist Heidi Peltier adds that battlefield expenditures represent only part of the overall burden. When long-term commitments such as veterans’ medical care, disability payments and debt servicing are included, the total cost of the conflict could approach $8 trillion — and the figure continues to grow.

Bloomberg also points out that the practice of financing wars without raising taxes persisted under subsequent U.S. administrations. At the outset of the Iraq war, publicly held national debt stood at $3.7 trillion. Today, that figure exceeds $30 trillion, equivalent to roughly 97 percent of the country’s GDP.