Beväpnad attack mot franska tidningen Charlie Hebdo. 12 döda (7/1)

CNN)—Many Americans likely think the tragedy at the satirical magazine Charlie Hebdo that played out in the streets of Paris on Wednesday is the sort of attack that could never involve a U.S. citizen.

Think again. Over the past four years two American citizens have been convicted in plots to murder Europe-based cartoonists who they believed had insulted Islam and two other Americans have been convicted of inciting violent attacks against cartoonists in the States who they felt had insulted the Prophet Mohammed.

A core tenet of the modern era, which was sparked by the Enlightenment of the 18th century -- much of which took place among the Parisian intellectuals who were the forebears of the fearless cartoonists of Charlie Hebdo -- was well expressed by a quote often attributed to the French philosopher Voltaire "I disapprove of what you say, but I will defend to the death your right to say it."

The killers in Paris on Wednesday reversed this key formula of the modern world: I disapprove of what you say and I will kill you for it.