IT WAS typical Aden. Bomb blasts, gunfire and fireworks lit up the night in a chaos of conflict and celebration. Southerners marched through Yemen’s second city proclaiming independence from northern taskmasters. Tanks punctured their cries with shells. Soldiers of the United Arab Emirates (UAE) joined in the mayhem, raining artillery fire on bases loyal to the vestiges of a central government that they had supposedly entered Yemen to protect.

The fighting that began on January 28th subsided after two days, leaving at least 36 dead. For the second time in three years officials loyal to the titular president, Abd Rabbo Mansour Hadi, prepared to flee from their offices. As The Economist went to press Mr Hadi’s presidential guard held out on just one small hilltop. But his government’s bases, the lucrative container port and the refinery were all under control of the Security Belt, a southern rebel militia trained and armed by the UAE.

As a result, Yemen is left with three centres of power and Mr Hadi’s coalition is split in two. The Houthis, a Shia rebel group supported by Iran, rule Sana’a, Yemen’s capital, which they captured in 2014. Ali Mohsin, a veteran warlord and the vice-president, oversees the remains of Yemen’s national army from the city of Marib (see map), east of Sana’a, together with his allies from Islah, a clutch of Islamist-leaning northern Sunni tribes. And now the Security Belt’s political arm, the Southern Transitional Council, is ruling the roost in Aden under a former governor, Aidarus al-Zoubaidi, and his Emirati patrons.

The big loser is Mr Hadi. He has no loyalists left on the ground. “An emperor with no clothes,” sneers a foreign observer. From his gilded exile in Riyadh, the Saudi capital, he still has choices. He could proclaim Yemen a federation and name Mr Zoubaidi as his deputy. Though Mr Zoubaidi has raised the flag of the former South Yemen, he is tempering his separatist rhetoric for now. He says he just wants Mr Hadi to shuffle his cabinet to bring his men on board.

But Yemen’s cracks go deeper. Bar the past 28 years, the south and north have rarely been united. For centuries Sunni Muslim fighters manned ribats, or citadels, on the coast and in the Hadhramaut region in the south and east. Their aim was to stop the northern imamate, which followed a Shia version of Islam known as Zaydi, from encroaching. Britain ruled the south, with its capital in Aden, as a separate colony for 128 years. South Yemen became a state of its own when Britain withdrew.

Unification of north and south in 1990 was meant to be a merger. But southerners saw it as a takeover by the more populous north. Even now, southerners consider themselves more cosmopolitan and northerners as qat-chewing highland tribesmen. They regard Mr Mohsin and his friends in Islah less as allies against the Houthis than as occupiers set on pilfering their oil. “The Yemen army should go and fight in the north, and leave the south to defend its own land,” says Haider al-Attas, a former president of South Yemen.

In an effort to marshal the south under his rule, Mr Zoubaidi has held an assembly in Aden for representatives of the south’s six provinces, and staged rallies in places Mr Hadi never visited during his six years in office. Although expelled from Aden, Mr Mohsin and Islah still have bases in the south that can threaten the separatists.

Southern warlords, too, will be loth to surrender autonomy to Mr Zoubaidi. Just as Aden wants to cut loose from the north, many southern cities crave independence from Aden. Hadhramis would like their provincial capital, Mukalla, to leave them alone. In turn Mahra, an eastern province, fears Hadhramaut. A Yemeni federation may be better than an anarchic break-up. But neither Mr Zoubaidi nor Mr Hadi may be able to halt the slide into chaos.