Final answer:
As a leader during World War I, the decision to join a war due to alliance obligations is complex, involving the potential for large-scale conflict and the long-term security implications of not supporting allies. Reasons justifying war often include defense, treaty obligations, and preventing dominance by a rival power. The web of alliances in pre-WWI Europe made large-scale conflict almost inevitable following a localized incident.
Step-by-step explanation:
As a leader of a European country on the eve of World War I, you face a difficult decision between maintaining peace and fulfilling alliance obligations. The complex network of alliances at the time made it so that supporting an ally often meant entering a large-scale conflict, and this is exactly what happened following the assassination of Archduke Franz Ferdinand. With countries bound by treaty obligations, the personal opposition to war becomes secondary when the entire continent risks being engulfed in turmoil. Adding to this dilemma are the long-term consequences of refusing to help an ally, which may lead to insecurity, diplomatic isolation, or even an invitation for aggression from rivals.
Reasons for going to war that might be justified include defense against aggression, fulfillment of treaty obligations that ensure mutual defense, and the prevention of a single power from dominating Europe, which could lead to a higher risk of oppression and conflict in the long term.
The decision to support friends or allies must be weighed against the moral implications, the potential for significant loss of life, and the strategic outcomes of either supporting an ally or abstaining from the conflict. In some cases, like in the complex situation preceding World War I, the entanglement of alliances virtually guaranteed that a localized conflict would escalate into a far-reaching war, making isolationism nearly impossible for those countries with treaty obligations.