Answer: the Spanish government.
Explanation:
Around the time when the USS Maine was sunk in 1898, there had been tension between the United States and Spain and the sinking only made this tension many times worse.
The USS Maine was sunk while it was at the Havana harbor in Cuba which was under the authority of the Spanish Government at the time.
Galvanised by the Yellow Journalism of the U.S. Press at the time, many Americans believed that it was the Spanish Government that ordered the sinking.
