Answer :
Alliances in WWI caused tangled commitments, escalating conflicts. Treaty of Versailles led to resentment, economic instability, fostering totalitarian regimes, and WW2.
The alliances formed prior to WWI are most to blame for the conflict, as they created a tangled web of commitments and escalations that turned a regional dispute into a global war. These alliances fostered a sense of obligation among nations to support each other, escalating conflicts beyond what they might have been if nations had been acting independently. Additionally, they limited diplomatic flexibility, leaving little room for peaceful resolution once tensions began to rise.
The negotiations after WWI, particularly the Treaty of Versailles, contributed to the start of WW2 by imposing harsh penalties and territorial losses on Germany, fueling resentment and economic instability, which were exacerbated by the Great Depression. Totalitarian regimes emerged in response to the economic and social turmoil, exploiting nationalist sentiments and seeking to overturn the perceived injustices of the Treaty of Versailles, ultimately leading to the outbreak of WW2.