Indonesia's battle with Islamic radicals is far from won.

The bombs that ripped through two Jakarta hotels Friday have also destroyed any illusion that Indonesia's war on terror is behind it. As President Susilo Bambang Yudhoyono looks ahead to his second term in office, the fight against terror is a clear priority.

Indonesia has been here before, of course, and Mr. Yudhoyono, popularly known as SBY, knows how to deal with it. Indonesians elected him after the 2002 Bali bombing as a bet for security. Although terrorist attacks continued, under SBY's watch Indonesia's counterterroism unit, Detachment 88, has arrested key leaders of the Islamist terrorist group Jemaah Islamiyah (JI). Friday's bombing was the first suspected JI attack since 2005.

But the war is far from won. Friday's attack was chillingly sophisticated: The terrorists checked into a room at the Marriott on Wednesday, smuggled bomb parts through security, and then assembled the explosives in the privacy of their room. They attacked with precision: One suicide bomber targeted a weekly breakfast for CEOs, leaving at least four foreign businessmen dead, many in the resources industry.

The attacks were also a reminder of the international nature of Islamic terrorism. Indonesian police suspect the man behind the attacks is Noordin Mohammed Top, a Malaysian citizen who has close ties to JI groups in the Southern Philippines, and al Quaeda in the Islamic Magreb, an al Quaeda affiliate in North Africa. A haven in any one of those places can feed violence elsewhere.

SBY addressed the nation Friday, vowing to "execute proper and decisive punishments to the bombers." Detachment 88 was already hot on Noordin's trail, raiding a suspected hideout just days before the attack that contained bomb components similar to those used Friday.

But Indonesia can do more than catch the criminals: It's also important to attack the Islamist ideology behind groups like JI and leaders like Noordin. For all of Indonesia's success in catching terrorists, the ideas that fuel their actions are still openly accepted. The ideological leader of JI, Abu Bakar Bashir, a cleric jailed for conspiracy after the Bali bombing, was released from jail in 2006 and is now free to preach hatred to all who will listen. Now that SBY is re-elected and won't run for another term in office, he has nothing to lose by speaking out against those who spread these ideas.

The U.S. can help, too, by continuing its practical and technical support for Detachment 88, and by taking seriously terrorist threats in hotspots like the Southern Philippines. President Barack Obama famously lived in Indonesia as a child, and will visit again in November. We hope this is a battle he understands.

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