That they were tired of the British being in China
Women can vote now and work in areas that before where considered only for men. African-Americans can now go to same schools as white people and eat at the same restaurants
To study data and patterns
President Theodore Roosevelt thought that the sinking of Maine was done by the Spanish fleet in 1898 February 15th.
He thought that if US doesnt fight back, they are no better than cowards.
He then ordered George Dewey to attack the Spanish.
But later realizing the Maine was sunk by a mine.
Basically this war is a revenge done by the Americans for their pride and the battleship Maine