Stevenson succeeded to the governorship on August 4, 1941, when O'Daniel resigned to take a seat in the U.S. Senate, which he won in a special election. In dramatic contrast to the flamboyant and unpredictable O'Daniel, Stevenson's approach was so conservative and taciturn that his critics accused him of doing nothing. Stevenson was elected to a full term in 1942, winning the Democratic primary with 69% of the vote and being unopposed in the general election. He was elected to a second term in 1944, effectively unopposed. When Stevenson left the governorship in January 1947, he was the longest-serving governor in the history of Texas and had presided over a broad and deep economic recovery during the years of World War II.