By the 1940s, organized baseball had been racially segregated for many years. The black press and some of their white colleagues had long campaigned for the integration of baseball. Wendell Smith of The Pittsburgh Courier was especially vocal. World War II experiences prompted more people to question segregation practices. In 1945, the Jim Crow policies of baseball changed forever when Branch Rickey and Jackie Robinson of the Negro League's Kansas City Monarchs agreed to a contract that would bring Robinson into the major leagues in 1947. In addition to racial intolerance, economic and other complex factors contributed to segregation in baseball. For example, many owners of major league teams rented their stadiums to Negro League teams when their own teams were on the road. Team owners knew that if baseball were integrated, the Negro Leagues would probably not survive losing their best players to the majors, major league owners would lose significant rental revenue, and many Negro League players would lose their livelihoods. Some owners also thought that a white audience would be reluctant to attend games with black players. Others saw the addition of black players as a way to attract larger white as well as black audiences and sell more tickets. In 1945, when Rickey approached Jackie Robinson, baseball was being proposed as one of the first areas of American society to integrate. Not until 1948 did a presidential order desegregate the armed forces; the Supreme Court forbid segregated public schools in 1954.--https://www.loc.gov/collections/jackie-robinson-baseball/articles-and-essays/baseball-the-color-line-and-jackie-robinson/1940-to-1946/