Why do you think john hay called the spanish american war a " splendid little war"?

On April 21, 1898, the United States declared war against Spain. It would be the first overseas conflict fought by the U.S. It involved major campaigns in both Cuba and the Philippine Islands. ... Their quest was described as a "splendid little war" by Secretary of State John Hay

It honestly depends on your definition for "splendid" but i think he said that because of the Naval victories and the invasion of Cuba was a success, with barely any flaws !

in mcculloch v. maryland (1819) the supreme court ruled that congress had implied powers under the necessary and proper clause of article i, section 8 of the constitution to create the second bank of the united states and that the state of maryland lacked the power to tax the bank.

gibbons v. ogden, (1824), was a landmark decision in which the supreme court of the united states held that the power to regulate interstate commerce, granted to congress by the commerce clause of the united states constitution, encompassed the power to regulate navigation.