The essay by Brigadier Nigel Aylwin-Foster of the British army, who served with US forces in Iraq from December 2003 to November 2004, appeared in the latest edition of the magazine Military Review, published by the US army.
Aylwin-Foster said US army personnel struggled to grasp the nuances of battling anti-government fighters while also winning the hearts and minds of ordinary Iraqis.
"Moreover, whilst they were almost unfailingly courteous and considerate, at times their cultural insensitivity, almost certainly inadvertent, arguably amounted to institutional racism," Aylwin-Foster wrote, arguing that the army exacerbated the task it now faces by alienating significant parts of the Iraqi population.
An army spokesman at the Pentagon, Paul Boyce, said "we may not agree with it" but the army wants to present candid views.
"The US army encourages alternate and diverse opinions so that we may find out more about our effectiveness, lessons learned and how to adapt in the future," Boyce said on Wednesday.
"We invited this particular commentary and published it in our magazine."
'US forces are more disposed to
use offensive operations' in Iraq
Britain has been the chief US ally in the Iraq war, launched in March 2003, and about 8500 British troops serve alongside 147,000 US troops there now.
Two dozen other countries also have troops in the US-led multinational force.
Other critics also have accused the US military of a lack of understanding of Iraqi and Islamic culture.
The military concedes that the vast majority of US troops do not know Arabic, and has launched an effort costing $750 million over five years to improve foreign language skills in the ranks.
Aylwin-Foster, whose rank equates to a one-star US general, referred to US army officers' "damaging optimism" that seemed out of touch with a more sobering reality.
"Self-belief and resilient optimism are recognised necessities for successful command, and all professional forces strive for a strong can-do ethos. However, it is unhelpful if it discourages junior commanders from reporting unwelcome news up the chain of command," Aylwin-Foster wrote.
"Force commanders and political masters need to know the true state of affairs if they are to reach timely decisions to change plans: arguably, they did not always do so," he added.
Aylwin-Foster faulted "moral righteousness" felt by US personnel that "encouraged the erroneous assumption that given the justness of the cause, actions that occurred in its name would be understood and accepted by the population, even if mistakes and civilian fatalities occurred in the implementation".
"[The US army] seemed weighed down by bureaucracy, a stiflingly hierarchical outlook, a predisposition to offensive operations, and a sense that duty required all issues to be confronted head-on"
Brigadier Nigel Aylwin-Foster,
British army officer
Aylwin-Foster said US forces in Iraq were more disposed to use offensive military operations than the forces of partners, and US rules of engagement "were more lenient than other nations', thus encouraging earlier escalation".
Aylwin-Foster lauded the US army's sense of patriotism and its talent, and said it was "in no way lacking in humanity or compassion".
"Yet it seemed weighed down by bureaucracy, a stiflingly hierarchical outlook, a predisposition to offensive operations, and a sense that duty required all issues to be confronted head-on."