The Bitcoin Civil War is a conflict between those who support the Bitcoin currency and those who think it is a long-tail marketing ploy. The war began when China began to produce superior ASICs that made it difficult for Bitcoin miners to make a profit. The white paper that inspired the creation of Bitcoin explained how proof of work could solve the scalability, speed, and security trilemma, but a small group of people have successfully inserted themselves as guard nodes and are manipulating the network to their own ends.
Kurt Wuckert Jr. explains the current Bitcoin Civil War between those in favor of Proof of Work and those in favor of Proof of Stake. He believes that the winner will be determined by which side can better confuse people.