Ex-general warns Trump learning the hard way to 'never underestimate your enemy'

22 July

President Donald Trump returns to the White House, after Israel and the U.S. launched strikes on Iran, in Washington, D.C., March 1, 2026. REUTERS/Nathan Howard

President Donald Trump is learning the hard way a lesson the military leaders know all too well, one retired lieutenant general wrote for The Bulwark: "never underestimate your enemy."

Mark Hertling is a retired U.S. Army lieutenant general who previously served as the Commanding General for the United States Army Europe. On Wednesday, he published a new piece for The Bulwark, warning the Trump administration that "swagger is not a strategy."

"As I watched Secretary of Defense Pete Hegseth testify before the Senate Appropriations Committee yesterday, I couldn’t help thinking about a tour in Iraq twenty years ago," Hertling wrote. "That was where I was taught a lesson that every soldier eventually learns, usually the hard way: never underestimate your enemy. Confidence is essential in combat, but swagger is dangerous because it tempts leaders into believing they already know what will happen, or how a battle or war will end. The enemy always gets a vote."

Hertling wrote of learning this "tough lesson" himself during deployments in Iraq, after militia leader Muqtada al-Sadr was able to rebuild his forces after suffering "enormous damage" from U.S. forces. This, he explained, taught him that "Tactical success does not automatically become strategic victory, and destroying enemy formations is not the same as destroying an enemy’s will or capacity to continue fighting," something that Trump's military leadership appears to have no regard for.

While being drilled about the operation in Iran, Defense Secretary Pete Hegseth described the country's "Revolutionary Guard as effectively defeated and destroyed," and hailed "the American campaign as a decisive success." Despite this, Hertling noted, "Iran remains capable of conducting military operations, threatening maritime traffic, and imposing costs on American forces, the war continues to rage unabated."

"Swagger may energize political supporters and produce memorable television clips, but it is not strategy," Hertling concluded. "Strategy begins with a clear understanding of the enemy, realistic assessments of what military force can accomplish, and enough humility to recognize that wars rarely unfold according to plan. More than two decades after learning that lesson in southern Iraq, I still remind myself never to predict the outcome of a war while the enemy is still fighting. Secretary Hegseth and President Trump would be well served to remember that lesson today."

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