What part did the alliance system play in the events that led to world war i? countries that were in alliances with other countr
ies were obligated to support their allies when war was declared. alliances enabled countries to cooperate in establishing large colonial empires. countries that were in alliances with other countries were guaranteed that they would not have to go to war. the countries in one alliance system were not allowed to trade with countries in competing alliances, which further divided europe.
The alliance system was important and played in the events that led to WWI because countries that were in alliances with other countries were obligated to support their allies when war was declared.
<h3>The First Battle of Bull Run (called First Manassas in the South) cost some 3,000 Union casualties, compared with 1,750 for the Confederates. Its outcome sent northerners who had expected a quick, decisive victory reeling, and gave rejoicing southerners a false hope that they themselves could pull off a swift victory</h3>