John McCain, speaking at the Canadian embassy in Washington last month, made his customary pitch for bombing the military assets of Syrian President Bashar al-Assad's regime and arming certain Syrian rebels. He expressed sympathy for Canada's strong reservations about getting involved militarily in Syria, "as Iraq and Afghanistan [have] shown." However, in a call to action, the Arizona senator referenced the interventions in Bosnia-Herzegovina, "where, we, with air power, went in and stopped genocide from taking place in the very heart of Europe." McCain concluded with the oft-misquoted warning: "There's an old line about those who refuse to learn the lessons of history are doomed to repeat them."
The actual passage comes from Volume One of George Santayana's The Life of Reason: The Phases of Human Progress (1905) and is worth quoting in its entirety:
"Progress, far from consisting in change, depends on retentiveness. When change is absolute there remains no being to improve and no direction is set for possible improvement: and when experience is not retained, as among savages, infancy is perpetual. Those who cannot remember the past are condemned to repeat it."
One realm in which "experience is not retained" and "infancy is perpetual" is Washington -- specifically, when it debates whether to militarily intervene in other countries. Proponents and (to a lesser degree) opponents of military intervention rarely assess simply what impact cruise missiles or smuggled guns may have on their political or military objectives in some distant country.