AMERICANS USUALLY regard their Civil War as one of the last of the romantic wars. Yet behind the romantic facade there lurks a beginning of the road to the excesses of bombing, body-counts, and pillaging in Vietnam. In particular, Maj. Gen. William Tecumseh Sherman's destructive marches through Georgia and South Carolina helped open the road toward My Lai.

Such is the central thesis of James Reston Jr.'s Sherman's Marches and Vietnam. The book is less a statement and defense of an argument, however, than a discursive essay on Sherman, the Civil War, and the Vietnam War as reflections of America. As the Civil War presents ambivalent images, furthermore, so Reston finds ambivalence throughout his development of his min theme. Sherman himself was of course an ambivalent figure: the scourge of the South, but also a man who had lived much in the antebellum South and grown to love it (or at least to feel the ambivalent love of a love-hate relationship). Sherman concluded his marches by offering Gen. Joseph E. Johnston generous surrender terms that went beyond military issues to look toward a civil settlement designed to head off the exacerbation of sectional animosities by the impending Reconstruction.

Reston finds Sherman a fascinating, even hypnotic figure; yet for most other Americans the general's charisma has faded, and in the very heart of Georgia and South Carolina the mention of his name rarely opposing Confederate army, Sherman felt as Westmoreland often did that he had accomplished about as much as conventional military science could expect -- yet he was frustrated because in spite of his conquests of places and armies the enemy still refused to abandon the struggle. How then could so exasperatingly intractable an opponent be brought to yield?

Sherman decided to try a campaign of terror. By cutting wide swaths of property destruction through the South, he would deliberately terrorize the enemy people, hoping that if he could frighten Confederate civilians enough, then the Confederate government and armies would collapse from lack of support. Sherman's campaign of terror, Reston is careful to make clear, was a decidedly limited one in that it involved remarkably little injury to persons. There were apparently few killings and rapes. Yet while Sherman's orders purported to keep destruction of property carefully regulated, wholesale pillaging and sometimes burning were both tacitly and directly encouraged. Thereby Sherman systematically violated a central principle of the international law of war, embodied also in American law: the inviolability of private property except under extreme circumstances of military necessity. By breaking down one of the major limits restraining the violence of war, Reston contends, Sherman accustomed American soldiers to regarding such limits lightly. He pointed the way to subsequent, larger violations, destroying lives as well as property. He accepted the burning of Columbia so offhandedly, even with a grim satisfaction, that the incineration of Hiroshima was foreshadowed.

Reston followed Sherman's trail to the United States Military Academy as well as through the South. At West Point he found among the faculty an inclination to teach about Sherman's marches with implied approval, notwithstanding the legal and ethical problems the marches raise. Officers who served in Vietnam appeared especially likely to sympathize with Sherman, because they had experienced frustrations similar to his. Experience in Vietnam could generate considerable regard for Sherman even among officers of Southern birth and background.

Reston feels much less regard for Sherman's campaign of terror, but he finds it necessary to strike yet another note of ambivalence. Sherman's marches, he thinks, at least had the virtue of resolving the frustrations that gave them birth, and therefore a resolution of the issues that had divided the nation also became possible. This reviewer is not so sure that Sherman deserves such credit; if the Confederacy had not already been tottering into its grave before the march to the sea began, the hatred spawned by Sherman's terrorism might well have turned out to make his efforts counterproductive. However that may be, resolution of differences did follow the Civil War. A similar resolution of America's internal stresses has not followed the Vietnam War, and some of the most eloquent passages of Reston's book return to searching the Civil War for possible guidance toward escaping the divisive emotional legacy of Vietnam.

Eloquent as those passages are, it might have been better if they and their at least partial apology for Sherman had not blurred the focus on Sherman's violations of the rules of war. If war is to remain with us, as seems likely, we need to return to those rules. A restoration of respect for legal and moral restraints on the conduct of war, and particularly a return to the principle of the immunity of noncombatants to injury to their persons and property, might offer one of the few means of curbing war short of holocaust. The lasting damage that Sherman perpetrated against restraint in war is a theme worth emphasizing. It is unfortunate that Reston has not hewed more faithfully to this theme; this is a stimulating book but a bit too indulgent in ambivalence and complexity.