The Soviets, indeed, understood a thing or two about the uses of the cult of revolutionary martyrdom. When vengeful anti-communists executed 26 imprisoned revolutionaries in 1918 -- the "26 Baku commissars" of subsequent legend -- the Bolsheviks immediately stylized their deaths into an epic of heroic political sacrifice.
But perhaps the most fateful (it not fatal) escalation of that same year took place after Fanni Kaplan's attempt to kill the Bolshevik leader, Vladimir Lenin, on August 30. Kaplan managed to hit him with two of the three shots from her Browning pistol, but Lenin survived the shooting. Like Corday, she was executed soon thereafter -- and Lenin, again following his hero Robespierre, used the occasion to launch an all-encompassing "Red Terror" aimed at counterrevolutionaries (which conveniently included many of his own enemies on the Left). Lenin's campaign swept away basic civil liberties for the better part of the next century.
A similar dynamic reveals itself again and again. On May 1, 1979, it was the assassination of Morteza Motahhari, Ayatollah Khomeini's beloved student and confidant, that prompted one of the major turning points in Iran's Islamic Revolution. Motahhari was one of the most important intellectual architects of Khomeini's plans for clerical rule, a role that made him a prime target for the radical leftist groups that were determined to shape the revolution in their own image. Motahhari was also something of an ersatz son for Khomeini, so it's hard to overestimate the emotional impact that his death had on the elderly ayatollah.
The revelation that a Marxist guerilla group was behind the killing confirmed Khomeini's deep-seated suspicions about the revolution's secular and leftist supporters, and prompted him to move ahead with his plans to defend clerical rule against them. Just four days later, he issued a decree establishing the Revolutionary Guard, a new armed force beholden directly to him. Later waves of attacks on officials of the new regime in the years that followed (especially a 1981 bombing that killed several top leaders, including Ayatollah Mohammed Beheshti, another one of Khomeini's favorites) triggered brutal reprisals and contributed to the deepening of the revolutionary police state.
By such grim standards, the portents for Tunisia are not the worst. The first reaction from Prime Minister Hamadi Jebali, a member of Ennahda, gestured in the right direction: He condemned Belaid's killing and declared those behind the murder to be "enemies of the revolution." He has since dissolved the government, promising to set up a new one that will be more inclusive -- only to have his own party reject that plan, creating even more uncertainty. Meanwhile, that hasn't done much to placate opposition protestors, who stormed Ennahda offices around the country. Belaid's brother has blamed Ennahda leader Rached Ghannouchi for the hit.
As things stand now, it appears unlikely that Tunisia will break out into civil war; so far the country's leftists have shown little inclination to violence. The more probable risk is that this could mark the start of a nearly insurmountable split within the revolutionary camp, with serious consequences for Tunisia's long-term instability. Ominously, the protestors now battling police in the streets are already calling for a "second revolution."