If Liu Bei really wrote to Cao Pi, then he would not be Liu Bei, and many of his men would also leave him. However, Cao Pi would rather miss the opportunity to destroy Wu than send troops. Since they were proclaimed emperors, they should have been busy taking Xiaoyi into consideration of the overall situation, and they were forced to offer the emperor's Zen throne but suddenly full of benevolence and morality, what medicine were they selling in this gourd?
Despite the opposition of his subjects, Liu Bei insisted on deposing Wu Liu Bei as empress, and the thought of Guan Yu's death was very painful, so he gathered 40,000 troops to avenge him. However, the Shu Han ministers were full of opposition, especially the strong opposition expressed by his close confidant Zhao Yun, who believed that Liu Bei's invasion of Eastern Wu was not the best policy.

First, the Shu courtiers believed that Emperor Xian of Han had been killed by Cao Pi, and in order to preserve the Han bloodline, they jointly persuaded Liu Bei to ascend the throne to inherit the unification. Now that Liu Bei was proclaimed emperor, he was bent on avenging Guan Yu and forgetting the national vendetta of Emperor Xian of Han, which obviously would not be supported by the ministers. Second, if Liu Bei followed the example of Liu Bang, the ancestor of Han Gao, and held high the banner of avenging the Emperor Xiandi of Han, he would gain the support of the people of the world, so the most urgent thing was to go out of Hanzhong, occupy Guanzhong, occupy the upper reaches of the Yellow River and Weishui, go down the river, and join forces with the Righteous Men of Guandong to fight against the rebellious state thief Cao Pi. Third, the war with Eastern Wu may not be able to win, and it also completely pushed Sun Quan to Cao Wei, no matter which country of Wu and Shu lost in the future, Cao Wei was a fisherman. But how easy is it to fight it again?
However, Liu Bei ate the scales and resolutely disagreed.
Why didn't Cao Pi send troops to fight Wu? It is said that since Sun Quan killed Guan Yu and captured Jingzhou, he was also interested and immediately sent someone to negotiate peace with Liu Bei. Zhuge Jin, as the representative of Eastern Wu, persuaded Liu Bei in various ways, and the routine was similar to Zhao Yun's idea, that is, to put aside a small vendetta, and the two countries would first jointly attack Cao Wei and then say. However, Liu Bei still did not accept it.
When Sun Quan saw that Liu Bei's side was determined to fight, he could only send emissaries to cao pi as subjects. Cao Pi was very happy and accepted Sun Quan's request, and planned to crown him king of Wu.
At this time, One of Cao Pi's advisers, Liu Ye, proposed that Cao Wei should not be a wall viewer, but should take advantage of the fire to rob Eastern Wu. He believed that although Cao Wei was stronger than Eastern Wu and Shu Han, the alliance between these two countries and the reliance on the Yangtze River and Qinling Ridge made it difficult for Cao Wei to advance south. Now that those two nests are in opposition, there must be no time to take care of or relax the defense of the Yangtze River Valley, and if my army suppresses the border, then Eastern Wu will be helpless and can only sit still. When Eastern Wu was destroyed, the Shu state was weak, and sooner or later it was Cao Wei's plate of Chinese food.
Cao Pi did not think so, he believed that to annex Eastern Wu, who had the intention of surrendering, would only chill the hearts of the people of the world, so it was better to cooperate with Eastern Wu to break the retreat of Shu Han.
Liu Ye believed that it was impossible, if he attacked the Shu state, then Liu Bei would definitely retreat, so that the two countries would be saved by the war subsiding, but if we sent troops to attack Eastern Wu, Liu Bei would definitely march into Eastern Wu immediately, one was to avenge Guan Yu, and the other was to fight for The territory of Eastern Wu.
Cao Pi did not accept Liu Ye's suggestion in the end, but chose to stay still for the time being. After Sun Quan's defeat of Liu Bei, Cao Pi decided to raise an army to attack Wu because Sun Quan did not send Sun Deng to the State of Wei as a hostage. However, the opportunity was fleeting, and although Cao Pi had 100,000 strong soldiers, he was no match for the fighting Eastern Wu army. Cao Ren returned from a great defeat, the general Zhang Liao fell ill and died on the battlefield, plus Zhu Ran died in Jiangling, and he could not fight for a long time. At this time, Sun Quan asked Cao Pi for peace, and Cao Pi went downhill with the donkey and shook hands with Sun Quan to make peace.
Conclusion: Liu Bei, who has always taken the restoration of the Great Han as his mission, disregarded the overall situation and did not care about the opposition of the Qunchen, insisting on cutting down Wu, and as a result, he destroyed the last bit of Shu Han's family foundation.
Cao Pi, who forced Emperor Xian of Han to take the throne, wanted to subdue people with virtue, and did not adopt the strategy of the strategist Liu Ye to join forces with Shu to cut down Wu, but insisted on joining forces with Wu and Shu, and the result was that he missed the opportunity to destroy Wu.
Sun Quan was left and right, Qu Yi pandered, plus the strongest corps in the history of Eastern Wu, the strength of Liu Bei and Cao Jiajun, who had experienced hundreds of battles, but one victory and one draw, thus laughing to the end. A few years later, Sun Quan was no longer willing to submit to the people, and succeeded Cao Wei and Shu Han, established the state of Wu, and ascended the throne as emperor.