The United States made a critical miscalculation by attacking Iran, having underestimated its capabilities from the outset, argues former Pentagon adviser and retired U. S. Army Colonel Douglas Macgregor. In an article published on Substack, he outlines six key reasons why, in his view, Washington has already effectively lost.

Macgregor’s first point centers on what he describes as a pattern of overconfidence shaped by past conflicts with weaker opponents, such as Afghanistan and Venezuela. This, he suggests, led U.S. decision-makers to misjudge Iran’s military potential, including its stockpile of precision missiles and drones, as well as its readiness for a prolonged confrontation. He frames the imbalance as a mismatch in expectations, with the U.S. preparing for a limited engagement while Iran approached the situation as a high-stakes conflict.

The second issue, he argues, is Washington’s failure to draw lessons from clashes with the Houthis in 2025. Those encounters demonstrated how the nature of warfare has shifted, allowing less equipped forces to wear down stronger adversaries through sustained, targeted strikes.

A third factor lies within the United States itself. Macgregor points to a lack of public perception of Iran as a direct threat, suggesting that Americans are unlikely to tolerate the long-term economic fallout of the conflict, including rising fuel prices. He illustrates this by referencing public frustration over increasing costs tied to the situation.

He also highlights what he sees as a fundamental misunderstanding of Iran’s status as a «civilizational state». In his view, countries like Iran, along with Russia, China, and India, possess a level of resilience that allows them to withstand extended external pressure. He further notes Tehran’s control over the strategically significant Strait of Hormuz.

Energy dynamics form the fifth pillar of his argument. Control over the strait gives Iran leverage over global oil supplies, which, he contends, disrupts established energy alliances and accelerates broader shifts in the global system, including weakening traditional structures such as OPEC and the petrodollar model.

Finally, Macgregor points to structural shortcomings within the U.S. military itself. He argues that its organization remains rooted in principles dating back to World War II and has not fully adapted to modern warfare. As a result, he sees a system focused on large-scale, legacy platforms rather than evolving to meet current challenges, warning that without reform, the U.S. risks repeating the outcomes of past conflicts such as Vietnam, Iraq, Afghanistan-and now Iran.