Who bore responsibility for the start of World War I?

By giving support via a blank check and having such a strong allyship between them, both Austria-Hungary and Germany had the motive and means to instigate a worldly conflict.

This position holds that Germany alone bears responsibility for the outbreak of World War I. It argues that Germany's aggressive foreign policy stoked tensions and coerced its ally Austria-Hungary into conflict, and that it was widely seen as the chief threat to European peace.

The tensions completely imploded with the assassination of a prominent Austrian by Serbian Nationalists. Without the rise of Serb nationalism, World War 1 would not have broken out.

Considering the interconnectedness of allyship, rising global tensions, and widespread imperialism, all actors must bear some responsibility for the outbreak of World War 1.