Democratic President Harry S. Truman's support of the civil rights movement, combined with the adoption of a civil rights plank in the 1948 Democratic platform, prompted many Southerners to walk out of the Democratic National Convention and form the Dixiecrat Party. This splinter party played a significant role in the 1948 election; the Dixiecrat candidate, Strom Thurmond, carried Alabama, Louisiana, Mississippi, and his native South Carolina. In the elections of 1952 and 1956, the popular Republican Dwight D. Eisenhower, commander of the Allied armed forces during World War II, carried several Southern states, with especially strong showings in the new suburbs. In 1956, Eisenhower also carried Louisiana, becoming the first Republican to win the state since Rutherford B. Hayes in 1876. The rest of the Deep South voted for his Democratic opponent, Adlai Stevenson. The 1948 election also marked Maryland's permanent defection from the Solid South, as the expansion of the federal government led to a population explosion that transformed the state into one that more closely resembled the Northeastern states politically.