What is the most important aspect of the Opium Wars?
The Opium War demonstrated the superiority of British military technology and tactics over those of the Chinese. The British were able to blockade the important inner waterways of China. Thus, they forced Manchu government to accept the unequal Nanjing treaty. The Chinese had to accept the demands for opening up China’s markets to foreign goods, including illegally imported opium. At the same time, they were also forced to permit Western missionaries to come to China and try to convert whomever they could to Christianity.
This treaty demonstrated to other Western powers, including the US and France, that the Chinese government was in a weak position and losing control over its foreign and economic policy. As a result, pressure was put on the Chinese government for new treaties and additional concessions. This, in turn, undermined the prestige of the Manchu government and inspired anti-Manchu rebels. The enormous Taiping Rebellion (1850–1864) and the ensuing decline and breakdown of traditional social and cultural certainties made the modernization of China inevitable; modernization offered the only possibility for addressing the challenge of Western imperialism. Immediately after suppressing the Taiping uprising, the Confucian bureaucratic reformers launched their policy of “self-strengthening,” which was the cautious first phase of their modernization campaign.
Thus the disastrous Opium War led to the humiliating defeat of the Qing government and forced concessions to Western powers, which in turn undermined the traditional social order. In this way, the Opium War set off a series of events that eventually led to the emergence of modern China.
To me, the most important aspect of the Opium Wars is that they were wars that were conducted so that Britain could force China to allow the British to bring opium into China to sell. The British needed to sell opium to China. When China banned the trade, Britain went to war.
Britain needed tea from China. They had to pay for it with silver and had nothing to sell the Chinese. This meant Britain's silver reserves were leaking away to China. So when the British found they could sell opium to Chinese, it was great for them. Now they had a way to get their silver back from the Chinese.
As I say, China banned the trade and Britain went to war to force them to resume that trade.
So, to me, the most important thing about these wars is that they were fairly immoral from our point of view -- they were fought to force China to allow Britain to sell drugs to the Chinese.
You could also argue that the most important aspect is that the wars ended with unequal treaties that gave the British all sorts of rights to China -- rights that essentially made parts of China subject to British law and not Chinese law.