As Augustus established a new governing order he effectively created a position as administrative head of state that had previously been occupied by several men. As princeps or 'first among equals' there was no official title of emperor as we know it today, and this distinction was very important in ancient Rome. Theoretically, the establishment of 'Empire' was only a temporary diversion from true Republican rule. After his death, it might be assumed that the government, and all the positions held by Augustus would revert to the old system. As Princeps, even under the new constitutional system, Augustus had no more right to establish a line of succession than was possible in the Republic. Being the first to hold such a position, however, allowed the new system to develop under a powerful and capable leader. As time passed, the concept of the Republic drifted farther and farther into oblivion. The long rule of Augustus, the elimination of opponents and the fear of a return to civil war and imperator generals seemingly destroyed any concept of a re-established Republic.
Augustus was alone made the head of the state, and there was no established order for succession. Naming a successor was akin to a provincial governor establishing his own hereditary rule. It simply didn't happen. By the time of Augustus death in 14 AD, however, it was absolutely inconceivable that there wouldn't be a replacement Princeps. Holding Tribunician power of the veto, administrative authority of the Consulship, religious domination as Pontifex Maximus and supreme command of the armies, the idea of Augustus really being just 'first among equals' was really a farce. While the Senate still officially had the right to name someone to that position, there were none who could possibly argue with the edicts of the divine Emperor himself.
The idea of succession evolved much in the same manner as naming a patriarchal heir in any Roman family. Augustus looked for choices both within and without his own family. The fact that he had no son, much like his own adoptive father Julius Caesar, would prove to be the biggest enduring challenge faced during his rule. While the potential for succession to the highest position in the known world existed, destabilizing domestic turmoil was the order of the day. Though the nature of attempting to curry Augustus' favor brought its own elements of intrigue, his own family's dysfunction played as much a part as the potential to be his heir.