Two major economic projects have lastingly impacted the 5th district and have indelibly dictated the politics of North Alabama for most of the 20th Century. Before 1933, the Northern Alabama counties were characteristically poor, white and rural. The Tennessee Valley Authority's (TVA) arrival changed much of that, slowly transforming the demographic towards technical and engineering employees. The second major project was the space and rocketry programs including Redstone Arsenal in Huntsville where the first large U.S. Ballistic missiles were developed. Additionally, NASA built the Marshall Space Flight Center in the Huntsville-Decatur area during the 1960s. In the late 1950s Northern Alabama came to be dominated by the high-tech and engineering industries, a trend which has continued up to the present. In recent years, the United Launch Alliance has located its research center in Decatur. As a result, Huntsville has become the second largest and fastest growing metropolitan area in Alabama.
For a time, the district bucked the increasing Republican trend in Alabama. It was the only district in the state that supported Walter Mondale in 1984, but hasn't supported a Democrat for president since then. Democrats continue to hold most offices at the local level, and continued to hold most of the district's seats in the Alabama state legislature until the Republicans swept nearly all of north Alabama's seats in 2010. In the mid-1990s, it was a seriously contested seat, with longtime Democratic incumbent Bud Cramer winning reelection by only 1,770 votes in 1994. However, Cramer was elected five more times with 70 percent or more of the vote and even ran unopposed in the Democratic landslide year of 2006. Cramer did not seek reelection in 2008. Parker Griffith, a retired oncologist and State Senator, won the open seat in November 2008. However, in December 2009, Griffith became a Republican. Until Griffith's switch, the district had been one of the last in the former Confederacy not to have sent a Republican to the U.S. Congress since Reconstruction. Griffith was ousted in the Republican primary by former Representative Mo Brooks.