The Red Wadi (Wadi al Ahmar) lies a bit to the west of the old Roman border between Tripolitania and Cyrenaica, but if Libya splits in two it will serve quite well as the new frontier. The deadline for the fighting to resume there was yesterday (March 27), but neither side is very good at organising a battle and we will have to wait for a bit. It will probably happen in the end, though.

Libya has been a chaos of rival militias holding down local fiefdoms ever since the overthrow of Moammar Gadhafi’s 42-year dictatorship in 2011, but in the past month the disintegration has accelerated. A formal division of the country into two successor states is now a real possibility, but it’s unlikely to happen without some further fighting.

There has been some already. Much of the eastern half of the country, Cyrenaica, has been under the control of a coalition of tribal militias led by Ibrahim Jathran since last year. He seized control of the terminals on the coast through which two-thirds of Libya’s oil production is exported, and set up the “Cyrenaica Political Bureau”, which is acting as a proto-government in the east.

The central government in Tripoli, which was led by Prime Minister Ali Zeidan, was powerless to stop him. The government has been paying $1,000 per month to about 160,000 members of various militias (out of a total population of only six million) in an attempt to make them servants of the state, but they don’t feel obliged to obey government orders. And the army that obeys Tripoli is too small and weak to take on a powerful warlord like Jathran.

Months of stalemate followed, while the country’s oil exports, which account for 95 percent of government revenues, plunged from 1.5 million barrels/day to only 200,000 barrels. (The Zintan militia in western Libya was also cutting pipelines and occupying oilfields from the western oilfields from time to time.) But matters came to a head when Jathran’s militia started trying to export oil itself from the eastern oil terminals in early March.

If he could sell Cyrenaica’s oil with impunity that would be the end of a united Libya, so Prime Minister Ali Zeidan threatened to sink a rogue tanker, the North Korean-flagged Morning Glory, that arrived at one of the terminals controlled by Jathran to load oil valued at $30 million. Libya’s navy had been sunk by NATO planes and its air force was near mutiny, however, so all Zeidan had to stop it was a tugboat jury-rigged with Grad rockets.

Morning Glory managed to get away, and the Islamist-dominated Congress that passes for a final authority in Libya fired Zeidan for his failure. Morning Glory was stopped later in the week by a U.S. Navy warship and handed over to the government in Tripoli, but it was too late for Zeidan, who fled the country fearing assassination.

Congress then ordered the most powerful militia in the west of the country, the Libyan Shield, to seize the rebel-held ports in the east, but after some clashes they were stopped east of Sirte. Since then the two sides have glared at each other across the Red Wadi, waiting for the deadline set by the speaker of Congress and de facto president, Nuri Abu Sahmain, to expire.

Now it has expired, and nothing has happened yet, but neither has there been any sign that the two sides are talking. Besides, it is misleading to talk of “two sides”: the country has become a jumble of militia-run city-states with rapidly shifting alliances. But the east-west split is real, and it is getting worse.

It goes back a long way. Even 2,000 years ago, in the heyday of the Roman empire, Tripolitania and Cyrenaica were two separate provinces, quite different in language and religion. Cyrenaica was Greek-speaking, and Tripolitania spoke Latin. After the empire became Christian in the 4th century AD, Cyrenaica became Orthodox while Tripolitania was part of the Roman (Catholic) church.

The Arab conquest of both provinces in the 7th century erased those differences of language and religion. All Libyans now speak Arabic, and the vast majority are Sunni Muslims. But the regional and tribal divisions of the country are very deep, and the residents of Cyrenaica have long resented the fact that most of the oil income flowed to the capital, Tripoli, and the rest of Tripolitania, while most of the oil was actually in Cyrenaica.

The Cyrenaica Political Bureau says it is a “federalist” organization that wants only the decentralization of the country and a bigger share of the oil revenues for the east, but in fact it is already halfway out the door—and the army units and air bases in the east support the rebels.

“We are assembling a large force to protect the ports,” said Senussi al-Meghrabi. “If they are attacked, it will be civil war.” But not a long civil war, probably, for there is virtually no chance that forces from Tripolitania could conquer Cyrenaica—especially when they are facing their own revolt back home from the powerful Zintan militia, allies of the exiled ex-prime minister Ali Zeidan. And they control the oil of Tripolitania.