More than 250 years separates the massacre at Fort William Henry in 1757 and the slaying of Osama Bin Laden in Pakistan in 2011, but according to Eliot A. Cohen, the author of “Conquered into Liberty: Two Centuries of Battles Along the Great Warpath,” the two events are not unrelated.

The unofficial motto of the US Army is, Cohen reminds us,  “Whatever it Takes.”

American armies learned to adapt to unforeseen and changing circumstances in the 18^th century, along the corridor between Albany and Montreal, at the center of which, of course, lies Lake George. They would abide by the legal and conventional norms of warfare until, or unless, forced to do otherwise, “resorting to ruthless means when that appeared necessary.”

“In 2011 a liberal American president had no compunction about ordering raiders into an allied country to kill, not capture, the architect of the September 11, 2001 terror attacks. The Navy SEALs who shot Osama bin Laden reported his death using as code for the founder of Al Qaeda the name of an Indian chieftain. Once again, the ruthless norms of frontier warfare trumped whatever compunctions international law and custom might have created,” writes Cohen.

According to Cohen, that approach to warfare can be traced, at least in part, to the massacre at Fort William Henry.

Disregarding the terms of surrender negotiated by Monro and Montcalm, Indians aiding the French attacked the survivors, killing 69 people and taking 200 prisoners.

In response to the massacre, and to frontier warfare in general, Cohen writes, “European soldiers found themselves accepting savage acts that they would have rejected in Europe, as when Amherst himself later proposed infecting the Indians with smallpox. Indian warfare had never recognized the punctilio of European military manners; the freedom and equality of life in the wilderness or on its edge… made English and French colonists willing to do what seemed practical, and avenge what appeared vicious, even if doing so meant stepping beyond the rules of war.” 

Whether anyone today would call the events of 1757 a massacre is questionable. But there is no doubt that it was seen as such by the colonists.

Another newly published book, “The Siege of Fort William Henry: A Year on the Northeastern Frontier” by Ben Hughes, helps explain why.

Based on the journals, memoirs and letters of witnesses, “The Siege of Fort William Henry: A Year on the Northeastern Frontier” captures the ferocity of the attack.

Relying upon contemporary sources, Hughes arrives at a higher number of dead, wounded and enslaved than does Cohen: 200 dead and 900 captured.

Regardless of how many were actually killed, descriptions of women’s “bellies being ript open” and children being “grabbed by their ankles and swung against trees until their brains were beat out,” which appeared in the colonists’ newspapers, could not help but outrage the Americans and give rise to the attitudes toward warfare discussed by Cohen.

But Cohen, who teaches at Johns Hopkins’ School of Advanced International Studies, is interested not only in how Americans make war, but why.

The conflicts along the great warpath suggest possible answers to that question, too.

Those of us who live in the valleys of Lake George and Lake Champlain and who grew up on the stories of battles at Fort William Henry and Fort Ticonderoga, tend to think of the Great Warpath as the route open to invaders from the north, and the forts as defensive outposts.

But as Cohen reminds us, that same corridor is also the most direct route from the US into Canada, and it retained its strategic value for the US well into the 19^th century.

“For well over a century, from the colonial period through American independence, the military struggle with what is now Canada, was America’s central strategic fact. For at least a half century beyond that, war between the United States and British-ruled Canada was a very real possibility,” he writes.

The phrase, “conquered into liberty,” was, in fact, coined by the American leaders who invaded Canada in 1775 in the unsuccessful effort to bring the provinces into alignment with the rebellious colonies.

Cohen concludes, “The abortive invasion of Canada combined, in a distinctively American way, idealism and calculating realpolitik.  The invaders sincerely advocated representative government and individual liberty, while manipulating local beliefs and brazenly attacking a neighbor… In years to come, Americans in many other places – from Mexico to the Philippines, Vietnam to Iraq – would behave similarly.” 

Although Cohen himself championed the invasion of Iraq (and is currently an advisor to Mitt Romney), I suspect he understands the reluctance of many Americans to engage in any other efforts to “conquer others into liberty.” The results of such ventures, as we learn from him, have been mixed, and too often, disastrous.