Because of the Crusades, the Christian as well as the Islamic world had 360 degrees changes and negative long-term effects. Before the crusades most of Christians were pacifists and regard Jesus Christ as the Prince of peace; but due to the Crusades, Christians' posture about violence totally changed. From their perspective violence could be justified if it was used just in wars to defend their church and God's mandates. Although at first, the Crusades were used in order for Christian pilgrimages to access the Holy city of Jerusalem, which was something good because the Muslims had taken control over the city and didn't let them in. Later on, the Crusaders lost their original path and promoted religious warfare for two and half centuries committing pillaging, murder among other atrocities not only against Muslims but also against any other vulnerable minorities.
Crusades also helped to elevate the authority of the papacy as the authoritative spiritual and temporal power in Europe before the emergence of the nation-states. Nowadays, because of the way Crusades develop most Muslims regard them as cruel and savage onslaughts by European Christians.
The correct answer to this open question is the following.
Although the question does not have any further references or attachments, we can say that the sectional conflict was a combination of an irrepressible conflict with the work of bungling politicians, fanatics, and agitators.
Before the Civil War, there were many incidents, events, and decisions that create more separation in the views of the northerners and southerners. In the North, the idea of abolitionism was supported by most states, while in the South, slavery was an important part of the economy. Indeed, southern states depended on slaves to produce the crops in large plantations. These crops had to be exported to Europe.
The Missouri Compromise or the Kansas-Nebraska Act was the product of different points of view from legislators trying to fix things until the problems too many that made seven states seceded from the Union, and later, the beginning of the Civil War.
John Wilkes booth shot Abraham Lincoln in his head.
