Philippine President Rodrigo Duterte salutes soldiers in Manila during a ceremony to destroy weapons confiscated from militants on Wednesday. (Aaron Favila/AP)

On Monday, Philippine President Rodrigo Duterte asked Congress to extend martial law — for a second time — in his home region of Mindanao. Two days later, Congress did just that. Mindanao is a restive southern province and home to 94 percent of the country’s Muslim population. Martial law is part of Duterte’s plan to ensure the “total eradication” of Islamist extremists — but this approach can backfire. Here’s why.

Why did Duterte first declare martial law?

In May, Duterte declared 60 days of martial law after security forces raided a suspected terrorist hideout. The raid was a failure: Instead of capturing the leader of the terrorist group Abu Sayyaf, Philippine troops found themselves in a firefight with different Islamists, the Maute group. Since then, 21 million Filipinos have been living under martial law, while government troops undertake a counterinsurgency campaign involving urban airstrikes and ground assaults. The militants recruited heavily, and an estimated 40 foreign fighters joined the conflict, including Indonesians, Malaysians and even a Saudi.

The conflict has been devastating. Those killed in the fighting, according to the military, include roughly 920 militants, 165 soldiers and 47 civilians. But that scarcely captures the disruption. According to the Office of the U.N. High Commissioner for Refugees, in the besieged city of Marawi, 98 percent of the 200,000 residents have been driven out. The city has been severely damaged, with some reconstruction cost estimates reaching $8 billion.

In mid-October, Duterte declared Marawi “liberated” but left martial law in place.

Duterte’s war on terrorism has its risks

Duterte says he has an unfailing commitment to fighting terrorism. He has claimed that he is 50 times as brutal as the terrorists, who have been known to behead their hostages. His parallel drug war, which followed his campaign promise to kill “drug pushers, hold-up men and do-nothings,” has claimed between 5,900 and 12,000 lives (including those of 60 children). The connections between criminal gangs and terrorist groups such as Abu Sayyaf, which relies on extortion and kidnapping, has allowed Duterte to aggressively pursue both.

As with the drug war, the war on terrorism in the Philippines is expanding. Duterte recently declared the Communist Party of the Philippines and its armed wing, the New People’s Army, a terrorist organization, 15 years after the United States made a similar declaration. The New People’s Army, which has attacked the Philippine state periodically since 1971, was previously the justification for President Ferdinand Marcos’s January 1972 declaration of martial law. Yet Marcos’s strongman rule, a dictatorship that lasted more than a decade and saw 70,000 Filipinos imprisoned and 34,000 tortured, ultimately failed to end what is now the world’s longest-running communist insurgency.

The current question in the Philippines is whether, even absent the terrorists and drug traffickers, Duterte’s instinct would be to abrogate democratic norms. As early as August 2016, he toyed with imposing martial law to overcome constitutional limits on his power. Critics of his request for an extension raised this fact, asking whether terrorism is a reason — or a pretext — for martial law. Just hours after the extension was approved, Duterte noted that the expansion of martial law throughout the Philippines was “on the table.”

The Philippine constitution allows the government to suspend habeas corpus — a suspension that permits the government to arrest and detain suspects without warrants — in the event of a rebellion. In those circumstances, the military can take over from civilian law enforcement and impose checkpoints that restrict freedom of movement. Suspending civil rights this way enables governments to act quickly to deal with extraordinary security threats — but also invites human rights violations. Perhaps more important, research finds that governments are actually more effective at preventing terrorism when there are legal limits on executive power.

War alone won’t defeat extremism

Duterte’s tactics are opening the door to further embitterment and radicalization. An aerial bombing campaign and extensive looting has devastated Marawi, giving the tens of thousands returning little to come home to. Observers fear this will only fuel radicalization in the region. Though international donors are stepping in to help with humanitarian relief and equipment, reconstruction will take years. Meanwhile, research has shown that force alone does not end terrorism. While Duterte is moving a once-stalled peace process with some militant groups forward, reintegrating former fighters and providing them with alternative livelihoods remain pressing challenges.

Violent extremism grows from both structural factors, such as corruption and government repression, and individual influences, like the desire to be a hero. Weak states, in particular, have conditions such as porous borders and poorly governed areas that allow violent extremist groups to operate. And evidence suggests that terrorists are more likely to come from low-income countries. In the Philippines, almost 20 percent of the population lives in extreme poverty, but Mindanao is the province with the highest concentration of the poor. In addition to local conditions supporting radicalization, Filipino Muslims are susceptible to recruitment by extremist groups in neighboring Indonesia and Malaysia.

An alternative approach to these challenges is the implementation of development programs to address some of these drivers of violent extremism. As is the case with other counterterrorism programs, evaluating the effectiveness of this relatively new strategy has been difficult. But there are indications that certain aspects of the approach could be effective, particularly in the areas of youth engagement and terrorist group disengagement. In the long run, a more balanced approach addressing the root causes of violence might prove more successful than Duterte’s militarism.

Jessica Trisko Darden is assistant professor at American University’s School of International Service and a Jeane Kirkpatrick Fellow at the American Enterprise Institute. Follow her on Twitter @triskodarden.