America entered into the Spanish-American War in 1898 for a variety of reasons including public opinion and concerns about our business and strategic interests, but the one key cause of us entering the war was yellow journalism.
The Spanish had been in Cuba for some time, and many Cubans began to resent them and revolt. This reminded Americans of when colonists revolted against Britain for independence. So public opinion was already on the side of the Cubans. Yellow journalists came along and shared the "atrocities" the Spaniards were doing in Cuba and the public outcry went from sympathy for Cubans to hatred towards Spain. The was further egged on when the U.S.S Maine exploded in the Cuban Bay and the yellow journalists inferred the Spanish were involved.
Yellow journalism also planted the seed that our business interest, in Cuba were in danger. At the time, America had around $ 100 million invested in Cuba in one way or another and $ 50 million in trade. Yellow journalists, with illustrations of crops burning and other economic damaging pictures caused panic.
Strategically, Spain was painted out to be a big group of gorillas, a group brutes by yellow journalism. We didn't want to have them in our backyard, they were a threat to us.
Though public opinion was already with Cuba, and concerns over our investments already existed, and we didn't want Spain in our backyard initially, the reporters and newspapers that were considered yellow journalism helped push along paranoia that already existed and pushed America into war with Spain.
4. Theodore Roosevelt's methods of acquiring the Panama Canal can bee labeled controversial, but not wrong. For hundreds of years countries have used their military presence to get their point across. Like the conquistadors of Spain and the Courer Du Bois of France, and the British when American colonists showed signs of revolts.
Roosevelt, a strong imperialistic republican took the canal as politically safe as he could, going to Britain, then France, followed with the Hay-Banau Varilla treaty.