The German documentary “The Unknown Soldier” arrives in American theaters at a poignant time. Michael Verhoeven’s exposé, about a nation coming to terms with its conflicted national memory and re-opening historical wounds that some would prefer to leave closed, arrives amid a similar debate among Americans involving the Iraq War and its link to a similar conflict a quarter-century ago in Vietnam.

After President Bush invoked the Vietnam War as evidence of how America must continue to support the current Iraq campaign, historians, sociologists, and political pundits rushed to question the comparison. Some pointed to the episode as another case of history being selectively rewritten, a snapshot of how easily historical facts can be reinterpreted, distorted, and even manipulated, depending on who is doing the recollecting.

So it was in Germany when, in 1999, the Wehrmacht exhibition was unveiled, taking direct aim at a line of conventional thinking within the German mainstream about World War II and the country’s role in perpetrating the Holocaust. While there continues to be something of a national shame in Germany concerning the atrocities that occurred under the direction of Adolph Hitler, “The Unknown Soldier” exposes a popular myth among the average German: the Holocaust was carried out almost entirely by the Third Reich’s Waffen SS, not the general army. With this belief safely in mind, the typical German family has successfully distanced itself from any implication in the Holocaust. If German fathers and grandfathers were not part of the SS, the myth seems to go, then they were not involved in the atrocities.

But the Wehrmacht exhibit shattered this popular mythology, unearthing for the general public an array of photos and films that showed average, Wehrmacht soldiers brutally tormenting, assaulting, and executing unarmed Jews. The exhibit constructed a devastating and all-but-irrefutable argument that the Holocaust would have been impossible if not for the aid and support of the wider army, and the willful acts of average infantrymen and officers who directly aided in the implementation of the so-called “final solution.”

From the outset, Mr. Verhoeven captures the way in which this exhibition landed like a depth charge in the Germany’s consciousness, its banner alone — which referred to “the German Army,” and not “parts of the German Army” — sparking protests from irate Germans who believed they were being told their beloved fathers and grandfathers were war criminals. The fury was widespread and persistent. Some claimed the exhibit’s documents were forgeries, that the videos were little more than propaganda, and that the photos — many of which show German soldiers standing next to mass graves — proved nothing. These officers merely discovered the carnage, some Germans claimed, they were not the cause of it. Mr. Verhoeven captures the surreal scene of these protests, persisting for months as so many in the German mainstream railed against the widespread implications of the evidence.

The director then turns his attention to the historical facts, bringing in historians and veterans to shed light on just what happened in those dark days. The resulting back-and-forth is gut-wrenching, a re-examination of the early, pre-gas chamber days of the Holocaust and the ways in which everyday anti-Semitism among common soldiers was stoked into radicalized violence at every level in the chain of command.

Mr. Verhoeven travels to the killing fields of Ukraine and Belarus, pauses for an extensive look at Babi Yar, where more than 30,000 innocents were lured into one of the largest mass executions in history, and incorporates numerous, shocking archival videos of everyday Jews being chased down by crowds, beaten, murdered, and loaded crudely onto carts for dumping. He listens first to those experts in denial, who say that any murders committed by the general army occurred solely due to rules of engagement; he then turns the camera to such measured historians as Wolfgang Wippermann and Hannes Heer, who detail how orders were filtered down through the army to “exterminate” as they marched east into the Soviet Union.

Seemingly overnight, the policy of the German army evolved, from one of “kill as you go,” to one of deliberately pausing in each town for the purposes of genocide. Once in the Soviet Union, the German army stoked anti-Semitic fears in the Russian population and then stood idly by as rabid Russian mobs took matters into their own hands.

Yet “The Unknown Soldier” is only partially a story about the distant past. The movie shows how the angry 1999 protests — undertaken in part by people who say their ancestors were just following orders — sparked counterprotests by average citizens, who insisted on attending the exhibit to counter the willful ignorance and denial of those outside. Among these visitors, more than a few are visibly shaken as they walk the halls, slowly coming to realize why their fathers never told them about the war, and why so many of these photos remained in family collections before being assembled for the first-ever public viewing. They seem to be awakening from a dream, tearfully realizing that the line between the honorable and the evil — just following orders, one expert insists, is not a valid excuse when the orders are immoral — is not as clear as they once thought.

The documentary’s title refers to Germany’s tomb of the unknown soldier, a monument that itself becomes a metaphor for the larger national debate inspired by the Wehrmacht Exhibition. It is the symbolic resting place of the unidentifiable corpses of German soldiers, but some historians point to it now as a symbol for the unknowable truth about the role of the German army in World War II: Since so few soldiers shared their experiences, we may never know the extent to which the army aided in the genocide. One historian points to a new definition for the unknown soldier: those few brave souls who stood tall and refused to carry out their orders, sometimes at the cost of their own lives. Mixed in with these unknown murderers, it seems, are a few unknown heroes as well.