How did this arrangement even make sense? It can't have been like the military coups of today, for a figure as universally revered as they were supposed to be, or was it?
I'm reading Romance of the Three Kingdoms (yep, probably the leading cause of questions re: that region in this sub) and the way the emperors get passed around between different hands like an object is almost a joke.
EDIT: I guess a better way to put this question would be: If Liu Bang was a warlord to begin with and became emperor through conquest, at what point did the position became purely ceremonial and lose control over the army?
What about the shoguns and the Japanese emperors?
Unfortunately, the similarities between Chinese and Japanese history regarding the power that warlords have are relatively limited, especially with the rise of the shogunate as a dominate power in Japan. However, I would suggest that for regarding Japan, you read the answers in [this thread] (http://www.reddit.com/r/AskHistorians/comments/22usym/) for some clarification of the roles of which the emperor and shogun played.
During the early Han, the Chinese state had more direct control over troop recruitment. As time passed, the landed aristocracy gained more autonomy and the state relied more heavily on them for troop recruitment.
You see, the Qin state destroyed the power of local aristocrats, but the Gaozu Emperor (Liu Bang) lacked the total authority of his Qin predecessors. The Han state therefore even in the beginning had a relationship with the landed elites that only grew as time went on.
The usurper Emperor Wang Mang tried to reverse the road to oligarchy with very radical land reforms, but he was defeated (indeed, his reforms served to alienate many peasants). The result was further decentralization during the later Han.
Much like in the late Roman Empire, the landed classes coalesced under strongmen who owned fortified estates. As a series of tribal invasions (plus Daoist uprisings) rocked the later Han, peasants relied totally upon local aristocrats for protection. The situation was increasingly similar to the later Zhou period.
Finally, warlords like Cao Cao were able to challenge the total authority of the Han state, thus China fragmented into three, and later 16 states. Despite the brief reunification brought by the Jin, China would remain broken politically until the Sui in the 7th century.
Francis Fukuyama goes into this in The Origins of Political Order.
Similar patterns are observable in other Chinese dynasties. However, China was among the first states to achieve total civilian control over the military apparatus. Warlords only arose during periods of chaos, and never really challenged the power of a stable dynasty (due, in part, to the Mandate of Heaven and such).
So, no, Chinese Emperors were not really pushed around by warlords all that much, only during times of the most severe political weakness.
The Romance of the Three Kingdoms takes places, as the title implies, during the Three Kingdoms period of Chinese History. Before this, the Han Dynasty had a firmly established, centralized empire China from 206 BC - 220 AD. The novel begins as Han power is waning: the last powerful emperor, He, died in 105, and his successors continued to be young heirs under the thumb of de facto elders. There were multiple contenders for the next "true Han heir," leading into an effective split of the area into three separate "kingdoms" which recognized different successors. Thus, it is not a representative of a time like the Han dynasty when there was a Chinese emperor, and the army was under state control. You might say that by the mid-2nd century the emperor had become ceremonial, since other relatives often had more power, but again, this was in the decline of the Dynasty and not its normal operation.