Joseph pulitzer and william randolph hearst had the most profound impact on

The US's declaration of war against Spain in 1898.

Explanation:

Joseph Pulitzer and William Randolph Hearst were the journalist of the New York World and the New York Journal respectively.

Both the media tried to compete with each other by printing false stories. This later came to be known as "Yellow Journalism".

in 1895-1898, Cuba demanded its independence and the Cuban Revolt began. Journalists such as Pulitzer and Hearst started printing fake stories.

In 1898, American naval ship named "Maine" sank in Harbor Havana. The reporters of Hearst blamed Spanish for the sinking of the ship without having any evidence to prove their claim.

The stories written by Pulitzer and Hearst not directly but in an indirect way was considered to be the reason of the US-Spain war in 1898.