THE coarse-talking, arse-kicking president of the Philippines is not the sort to worry unduly about the finer points of the law. Yet Rodrigo Duterte is making plain his priority in 2018: changing the constitution in ways that will reshape the state. Last month Mr Duterte announced a committee of politicians and worthies to feed ideas to Congress. The plan is for Congress, armed with the committee’s recommendations, to turn itself into a constituent assembly empowered to draft revisions. The country will then vote on its proposals in a plebiscite. The task may consume the rest of Mr Duterte’s presidency, at a time when much needs fixing elsewhere. Many Filipinos are scratching their heads. Others question Mr Duterte’s motives.

The least contentious of the president’s three desired changes is the easing of the constitutional limits on foreign ownership of companies, to attract foreign capital and encourage competition. The other two goals are radical. One is to remove some of the president’s powers and hand them to a prime minister, creating a hybrid presidential-parliamentary system along the lines of France, Taiwan or South Korea. The other is to turn the Philippines’ centralised government into a federation of perhaps five newly created states.

Rumba in the jungle

Talk of “cha-cha” (short for “charter change”—amending the constitution) is not new. The current constitution was promulgated in 1987 under Cory Aquino after the People Power revolution. It aimed to prevent a repeat of the tyranny the country had suffered under Ferdinand Marcos. The president was limited to a single six-year term. A bicameral Congress was created in the place of the unicameral one that Marcos had manipulated. Martial law can be declared only with its approval.

The first push for cha-cha came towards the end of the term of Aquino’s successor, Fidel Ramos. His supporters, too, advocated a hybrid presidential-parliamentary model. The idea has never gone away. Constitutional specialists backing Mr Duterte claim that the change would remove the president as the fount of patronage in a winner-takes-all system. Above the fray of day-to-day politics, he could play the wise statesman, guiding foreign policy and guarding Philippine sovereignty. Parties, it is hoped, would acquire more ideological heft, to help build a majority in Congress, instead of simply seeking the president’s favour. In this set-up, the prime minister could be removed by a vote of no confidence—no need for any more coups or mass protests.

Mr Ramos’s attempts at change were scuppered by suspicions that he wanted the post of prime minister himself, in order to extend his time in power. Mr Duterte’s motives are even more likely to come under scrutiny. A populist and an autocrat, he scoffs at the law, encourages extrajudicial killings of drug users and makes light of human rights. It is hard to imagine him regretting a powerful presidency—and many Filipinos love a strongman.

But Mr Duterte is merely making suggestions, his backers say. Anyway, Congress, not the president, has the power of cha-cha. Yet congressmen fawn on Mr Duterte. Some are bound to propose extending his term, which ends in 2022, or abolishing term limits for the presidency. Meanwhile, little would stop the nakedly self-serving legislators from rewriting the constitution to suit themselves—for instance, by bringing back a pork-barrel fund that the Supreme Court ordered scrapped five years ago.

The idea of a federal Philippines is appealing. Power—political and economic—is now centralised in “imperial” Manila, the capital. Almost every function of government, from education to the police, is administered from the metropolis, despite the country’s mosaic of peoples and languages. Mr Duterte’s calls for reform went down well in the provinces during his election campaign. His own base of Davao, in the far south of the country, feels far from the capital.

Look closer, though, and doubts multiply. For one, what is to stop families who already dominate politics and business in their localities from further entrenching their power in the newly created states—Mr Duterte’s included? The president’s main argument for sweeping federal change is oddly narrow: to bring peace to the troubled Muslim areas of Mindanao, the island on which Davao is the biggest city, home to a decades-old Islamist rebellion. A national political consensus has long held that disaffection in Mindanao can only be countered by autonomy for the 4m-odd Muslims there, coupled with economic development.

The issue is whether the constitution blocks such an outcome. A decade ago a peace pact with the main insurgents, the Moro Islamic Liberation Front (MILF), offered more autonomy to Muslim areas in return for abandoning the armed struggle for independence. Yet the agreement was knifed by the Supreme Court, which ruled that, since it created a state within the Philippine state, the pact was unconstitutional. In response, one faction of MILF broke away, and now runs the small but potent Islamic State franchise in Mindanao.

A new and more comprehensive agreement was struck with the MILF in 2014. The worry is that the court will deem the enabling legislation unconstitutional, too. The MILF has yet to threaten publicly to go back to war, but is impatient with the peace process. For the president, peace is a big enough prize to justify changing the constitution.

Is he right? Surely not, at least until the national legislation putting the agreement of 2014 into effect has actually been passed and tested before the Supreme Court, which is increasingly wary of crossing the president. Even then, overhauling the political system that governs 100m people to please 4m of them seems extreme—and probably will not appease the armed groups outside the peace deal anyway. Filipinos would be running the risk of a constitutional coup for meagre and uncertain benefits.