Compare the United State's decision to participate in the Spanish American War and in WW1

On April 21, 1898, the United States declared war against Spain. ... The reasons for war were many, but there were two immediate ones: America's support the ongoing struggle by Cubans and Filipinos against Spanish rule, and the mysterious explosion of the battleship U.S.S. Maine in Havana Harbor.

congress also has implied powers, which derive from the necessary and proper clause of the constitution and permit congress "to make all laws which shall be necessary and proper for carrying into execution the foregoing powers, and all other powers vested by this constitution in the government of the united states.