In a 1 1/2 mile stretch of road north of the seacoast city of Jubeil there are three checkpoints - each controlled by a different Lebanese military group.
The color of their camouflage fatigues tells passers-by whether they are being stopped by the Lebanese Army, the Christian Phalange militia, or the Marada Christian militia. Farther up the road is the first of many checkpoints for the Syrian Army.
The various checkpoints are one indication of the complex political and military balance that persists in northern Lebanon. As the new government of President Amin Gemayel continues its efforts to unify and rebuild Beirut under one central authority, this area in the north and its main city, Tripoli, are anything but united.
The Lebanese Army and police force have a token presence near Tripoli. They patrol some neighborhoods, as do the Syrians, Palestinians, and Muslim militiamen. Outside the city in the hills and mountains to the east is a large region controlled by 1,000 full-time Marada militiamen. Marada is the Arabic nickname for ''Maronite giants of the mountains.''
Incorporating these disparate groups into a united Lebanon depends at least in part on current US attempts to negotiate a Syrian and Israeli withdrawal, which would allow the Lebanese Army to reassert its authority here. But even without this major step, there are positive signs of conciliation among various factions.
[A Phalangist Party newspaper reported Oct. 12 that Syria had released nine party members east of Beirut. The move appeared to be a major concession by the Syrians and an indication of improved relations between the two groups.]
In another conciliatory move, Suleiman Franjieh, leader of the Marada militia and a former president of Lebanon, last week telephoned current President Gemayel and pledged his full support and cooperation to the new government.
The call is seen here as a rapprochement between the Franjiehs and the Gemayels, whose families have been feuding since the 1978 slaying of Mr. Franjieh's oldest son, part of his son's family, and 30 others east of Tripoli.
Mr. Franjieh has said he believes Bashir Gemayel, then commander of the Christian Phalange militia, was behind the attack. As such, Franjieh opposed the election of Bashir as president. But Christian Maronite sources say the death of Bashir in a Beirut bomb blast last month made it easier for Franjieh to support the presidency of Bashir's older brother, Amin.
For President Amin Gemayel the telephone call means that another piece of war-shattered Lebanon may be falling into place. Franjieh's people say they will support the return of the Lebanese government and Army troops to the north both in Tripoli and throughout the central mountains they now control.
Still, there remain significant problems to the establishment of Lebanese sovereignty in the north.
* One obstacle is the estimated 3,000 Palestine Liberation Organization fighters who are still in northern Lebanon. Some of them reportedly reentered Lebanon through the northern border with Syria after being evacuated from Beirut in late August. It is unclear whether the PLO fighters will decide to pull back if the Syrians leave.
* Another problem is the Syrians. If they intend to pull out soon, their positions north of Tripoli do not indicate it. There are freshly bulldozed trenches for several miles along the road between the Nahr Al-Bared refugee camp and the Syrian border. Their heaviest concentration appears to be near the former Lebanese air base at Kleilat on the plain between the sea and the mountains.
* Also troubling is the outbreak in Tripoli last week of violence betweeen the Sunni Muslims and Muslims of the Alawite sect. The Alawites are a minority in Tripoli but they dominate the business community in Tripoli. This has led to resentment among Sunnis and caused tension between the two groups.