Final answer:
The primary cause of the Spanish-American War was the explosion of the USS Maine battleship near Cuba.
Step-by-step explanation:
The primary cause of the Spanish-American War was the explosion of a US battleship near Cuba, for which Spain was blamed. The explosion occurred on the USS Maine in Havana Harbor in 1898. While the exact cause of the explosion is still unknown, US newspapers sensationalized the incident, leading to a public outcry for war against Spain.
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