Indonesia notched another big victory in the antiterror fight this week with the re-arrest of Abu Bakar Bashir, the al Qaeda-linked spiritual leader linked to the 2002 Bali bombings, as the Australian National University's Greg Fealy explains on a nearby page. If only the country's leaders would pursue Islamic vigilante groups just as aggressively.

Since Suharto fell in 1998, these thugs-for-hire have proliferated in the world's most populous Muslim-majority country. The most prominent, the Islamic Defenders Front (FPI), yearns for a Shariah state, and has been fingered for burning down Christian churches; attacking the Ahmadiyya, a minority Muslim sect; and beating up peaceful NGO activists. The latest misadventure came Sunday when goons beat up 20 Christians in Bekasi, West Java. (FPI denies involvement.)

Far from distancing themselves from this kind of behavior, public figures have recently started to court the group. Jakarta Governor Fauzi Bowo and Police Chief Timur Pradopo attended FPI's 12th anniversary celebration Saturday, giving the group a taste of political legitimacy. The governor even invited FPI into the capital to police Muslims' behavior during Ramadan, which began on Wednesday.

Thankfully, the majority of Indonesians are moderate and perceive the real threat FPI presents to their way of life and precious civil liberties. Twitter groups, editorial pages and NGOs erupted in protest over the Jakarta governor's invitation. FPI head Habib Rizieq was forced to back down and pledged to let the police enforce Ramadan laws.

That's all to the good. But what happens the next time FPI hooks arms with the police and local politicians? President Susilo Bambang Yudhoyono has voiced "concern" over violence against minorities, as he did after Sunday's attack, but has largely bowed to the police to enforce the rule of law. Parliament has made similar noises. The result? As the Wahid Institute has chronicled, attacks are creeping upward, to 60 incidents last year from 55 in 2008. And that doesn't even count attempts to impose Shariah through legislation, which has proliferated in recent years.

This cycle won't be broken until President Yudhoyono exerts some leadership. This could be tough for a president who has tried to court the hardline Muslim vote since he first took office in 2004, from freezing the activities of the Ahmadiyya to enacting a radical antipornography law that limits free speech.

But as Yenny Wahid, the daughter of former president and respected cleric Abdurrahman Wahid, told us earlier this week, groups like FPI "carry the banner of Islam; therefore they act with impunity." Surely that makes the violent FPI just as dangerous as men like Mr. Bashir.

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