After the conquest of Gaul, how did the Roman Government maintain control of the area during the civil wars and period of time after the assassination of Caesar? One would think that the tribal leaders would have taken that opportunity to again rise against the Romans while they were distracted with their own internal power struggles.
The most important factor is that not every Gallic leader was anti-Roman, Caesar's campaigns were always heavily supported by his Gallic enemies. These divisions both divided the different states against each other--for example, the Aedui were pro-Roman and the Sequani were anti-Roman--and divided them among themselves--the Aedui had both a pro and anti-Roman faction. Vercingetorix's rebellion essentially ended in the decimation of much of the anti-Roman Gallic factions.