Answer: e the American public and many leading Republicans demanded it.
Step-by-step explanation:
Thanks to yellow journalism twisting the facts of the explosion of the USS Maine at the Cuban capital of Havana in 1898, the American public were overwhelmingly in favor of going to war against the Spanish who tried their best to avoid this because they knew they would suffer defeat.
The efforts of the Spanish were fruitless however because many leading Republicans sided with their constituents and called for war in both House of Congress. President William McKinley then bowed to this pressure and asked for a declaration of war.