It happened in both World War I and World War II. From Martin Sieff at strategic-culture.org:
NATO’s obsession with pulling in as many small, unstable and potentially extremist countries in Eastern Europe as possible makes a world war inevitable rather than deterring one.
The reason for this could not be more simple or clear: Small countries start world wars and destroy the empires and great nations that go to war to defend them.
Belgium doomed England and Serbia doomed Russia in 1914.
The Russian Empire, the largest nation in the world in terms of area and the third largest after the British Empire and China in terms of population at the time, went to war to defend Serbia from invasion by Austria-Hungary.
This was a spectacularly unnecessary and catastrophic decision: Count Witte, the great elder statesman of the czarist aristocracy was completely against it. So was the notorious, but ultimately well-meaning mystic and self-proclaimed holy man Gregory Rasputin., He frantically cabled Czar Nikolai II to not take the fateful decision.
Russia in truth owed Serbia nothing beyond a general feeling of solidarity for a fellow Slav nation. The Serbian government’s attitude towards Russia was far different. They were determined to pull Russia into a full-scale war with Austria-Hungary to destroy that empire. There is no sign that anyone in the Serbian government expressed any concern or regret then or ever afterwards for the 3.4 million Russian deaths in the war, not to mention the many millions who were killed in the Russian civil war, British, Japanese and French military interventions and the terrible typhus epidemic of 1920 that followed.
Indeed, Serbia, in modern terms, was a terrorist state in 1914. Serbian Military intelligence financed, organized and armed the Black Hand terrorist group that gunned down the Archduke Franz Ferdinand, the heir to the Habsburg throne in the Austro-Hungarian Empire. Austro-Hungarian intelligence was so incompetent they were never able to prove the connection at the time.
Britain’s descent into the chaos of World War I was even more unnecessary than Russia’s. Britain had no treaty commitment to go to the aid of France but it did have a treaty guaranteeing the security of tiny Belgium. However, that 1839 Treaty of London was 75 years old – even older than the NATO alliance is today and the British were free to ignore it.
Instead, the British therefore went to war in 1914, amid an orgy of public sentiment to defend “gallant, little Belgium.”
To continue reading: Great Nations Are Destroyed by Being Pulled into Wars to Defend Tiny Ones