Thursday's massacre by Muslim extremists at the Paris office of a satirical newspaper was an attack on the right of free expression. There is no right more fundamental to maintaining liberty. In that regard, the attack was an attack on this newspaper, on the readers who share their opinions in letters and online reader comments, and on all those who hold dear the right to disagree, to denounce, to lampoon.

The alternative newspaper Charlie Hebdo had its roots in the global youth uprisings of the late 1960s and early 1970s and was true to the anti-authority tenor of those times. It had particular disdain for religious authority and by all accounts was an equal opportunity basher in that regard.

By American mainstream media standards, and among many in France, some of its caricatures would be considered crude and needlessly provocative. A recent cover reportedly displayed a strange-looking Virgin Mary giving birth to a bizarrely depicted Christ. France, this nation's oldest ally and one of the cradles of liberty, has a long history, dating to the French Revolution, of using biting satire to make a point.

The nature of Charlie Hebdo's free speech, however, is irrelevant to the issue at hand. No one should fear for his life for saying or displaying something others may find offensive. If such fear prevails, liberty withers.

The French newspaper's unforgiveable sin, at least in the narrow minds of its attackers, was its illustrations ridiculing the Muslim faith and the Prophet Muhammad. In 2011, angry Muslims firebombed its offices after it spoofed Shariah law.

This time the penalty for publishing offensive caricatures of the Prophet was death. The terrorist commandos barged in as the magazine's staff gathered for a lunchtime editorial meeting. They separated men from women and called out the names of cartoonists they intended to kill, according to news accounts. Those fatally shot included cartoonists Jean Cabut, 76, and Georges Wolinski, 80.

Two responding police officers were also murdered. In total, 12 died, with nearly as many wounded.

To their credit, even with the killers still at large, the French people refused to be cowed. They held large rallies around the country. Many displayed the statement, "Je Suis Charlie" - which translates as "I Am Charlie."

It is how the world must respond. Free people must defend free expression in all its forms. Commentators and cartoonists must, fearlessly, continue to ridicule and rhetorically eviscerate this virulent segment of the Muslim faith that casts itself as the arbiter of what people can say and believe.