IT WAS a year ago Saturday that fruit vendor Mohamed Bouazizi set himself aflame in the Tunisian town of Sidi Bouzid, improbably providing the spark for what has become a regional revolution. The Arab Spring acquired its name in part because early commentators likened it to the upheavals that brought an end to dictatorship in other parts of the world — including the former Soviet bloc, East Asia and Latin America. It seemed logical that Middle Eastern states would, at last, follow the same path that led in other places from dictatorship and economic stagnation to free elections, free markets and integration into a global economy.

A year later, it’s clear that the Arab revolutions are different in some fundamental ways — and may not deserve the label of “spring.” Democratic transformations in other parts of the world since 1980 were largely peaceful, as autocrats from the Philippines to Chile yielded to “people power.” But while that paradigm mostly worked in Tunisia and in Egypt early this year, the subsequent months have been dominated by scenes of slaughter, as Libya’s Moammar Gaddafi, Syria’s Bashar al-Assad and Yemen’s Ali Abdullah Saleh have chosen to fight — even to the death — rather than give up. Mr. Gaddafi is gone, and the Assad and Saleh regimes may soon follow. But the thousands of deaths they caused have cast a pall over their countries; no one yet knows when and how the killing will end or whether there will be reconciliation.

A second difference in the Arab transformation is the worrying economic prospects of newly liberated countries. Eastern European and Asian countries adopted liberal market policies that led to booming growth; so, after a few years of drift, did most of Latin America. But Egypt and other Arab states so far are leaning toward a populism that could inhibit foreign investment and trade. They are also unlikely to receive as much Western aid as helped the new democracies of the 1980s and ’90s. Libya will prosper with oil. But many young Arabs may find that their aspirations for jobs remain unmet.

A final distinction is the nature of the political movements coming to power in the revolution’s aftermath. Though the Islamists of Tunisia, Egypt, Morocco and elsewhere say that they are democrats, they are not liberal — and their relations with the West are uneasy at best. The true liberals of the Arab world — those who plotted the uprisings on Facebook and brought the secular middle classes to the street — risk being marginalized. They lack the organization of mosque-based movements or the foreign funding supplied by conservative states such as Saudi Arabia and Qatar. In Egypt, they also remain the prime target of a military establishment that hopes to preserve an outsize measure of power.

In retrospect, it’s not surprising that the Middle East’s modernization is proving bumpier than elsewhere: The troubles reflect some of the reasons that the 20th-century model of autocracy lasted decades longer there than in Latin America or Asia. But the messiness should not be a reason to regret the revolution, or worse, support the attempts of the Egyptian or Syrian armies to check the Islamists or “restore order” by force.

The best cure for what ails the Middle East is what it has lacked: free debate and democracy. In the short term, that may lead to mistaken policies or greater friction with the West. But over time extremists and fundamentalists are more likely to be discredited. The Arab world’s huge and rising young generation wants the freedom and prosperity it sees spreading in much of the rest of the world — and the rest of the world should be betting on that.