On February 19, 1945, 30,000 Marines splashed ashore on a small volcanic island in the central Pacific. After four days of bitter fighting, a small patrol reached the peak of Mt. Suribachi, where it planted a U.S. flag in an iconic scene captured by photographer Joe Rosenthal. This famous image was hardly the end of the battle. Iwo Jima would not be secure until March 26. Almost all of the 21,000 Japanese defenders elected to die rather than surrender. Rooting them out cost more than 6,000 American dead and 20,000 wounded, making this the costliest battle in the storied history of the Marine Corps.

It is right and proper that there should be 60th-anniversary commemorations of these heroics. For, as Fleet Admiral Chester Nimitz famously said, ” … on Iwo Island, uncommon valor was a common virtue.” Yet it would be a mistake to bury this battle in a haze of “Greatest Generation” sentimentality. Our awe at the bravery of the Marines and their Japanese adversaries should not cause us to overlook the stupidity that forced them into this unnecessary meat grinder. Selective memories of World War II, which record only inspiring deeds and block out all waste and folly, create an impossible standard of perfection against which to judge contemporary conflicts.

That is why Marine Captain Robert S. Burrell, a history instructor at the Naval Academy, has performed a valuable service by publishing in the October 2004 issue of the Journal of Military History an article called “Breaking the Cycle of Iwo Jima Mythology.” Mr. Burrell examines the planning of Operation Detachment, as the invasion was known, and shows that it was badly bungled.

The planners actually thought that Iwo Jima would be lightly defended. Nimitz had no idea that the Japanese had been preparing an elaborate defensive network of caves, bunkers and tunnels. As a result, he failed to allocate enough aircraft or warships to seriously dent the enemy defenses before the infantry landings. This oversight consigned the Marines to what a war correspondent called “a nightmare in hell.” And for what?

The rationales for taking the island were shaky at the time and utterly specious in hindsight. The original impetus came from the U.S. Army Air Forces, which wanted a base from which fighters could escort B-29 Super fortress bombers on missions over Japan. But Iwo Jima was so far away from most Japanese targets – a 1,500-mile round trip – that even the newest fighter, the P-51D Mustang, lacked sufficient range and navigational equipment for that purpose. In any case, Japanese air defenses were so weak that B-29s didn’t need any escort; they were able to reduce Japanese cities to ashes on their own.

When the fighter-escort mission didn’t pan out, U.S. commanders had to come up with another rationale for why 26,000 casualties had not been in vain. After the war, it was claimed that Iwo Jima had been a vital emergency landing field for crippled B-29s on their way back from Japan. In a much-quoted statistic, the Air Force reported that 2,251 Superforts landed on Iwo, and because each one carried 11 crewmen, a total of 24,761 airmen were saved.

Mr. Burrell demolishes these spurious statistics. Most of those landings, he shows, were not for emergencies but for training or to take on extra fuel or bombs. If Iwo Jima hadn’t been in U.S. hands, most of the four-engine bombers could have made it back to their bases in the Mariana Islands 625 miles away. And even if some had been forced to ditch at sea, many of their crewmen would have been rescued by the Navy. Mr. Burrell concludes that Iwo Jima was “helpful” to the U.S. bombing effort but hardly worth the price in blood.

In modern parlance, you might say that Iwo Jima was a battle of choice waged on the basis of faulty intelligence and inadequate plans. If Ted Kennedy had been in the Senate in 1945 (hard to believe, but he wasn’t), he would have been hollering about the incompetence of the Roosevelt administration, which produced many times more casualties in five weeks than U.S. forces have suffered in Iraq in the last two years.

No such criticism was heard at the time, in part because of the rah-rah tone of World War II press coverage but also because Americans back then had a greater appreciation for the ugly, unpredictable nature of combat. They even coined a word for it: snafu (in polite language: “situation normal, all fouled up”). It’s a shame that so many sentimental tributes to the veterans of the Good War elide this unpleasant reality, leaving us a bit less intellectually and emotionally prepared for the trauma of modern war.

Mr. Boot is a senior fellow at the Council on Foreign Relations and a columnist for the Los Angeles Times, where this first appeared.