In Alabama, members of both the House of Representatives and the Senate serve four-year terms, running in years corresponding with presidential midterm elections.

Four of the gains made by Republicans were in rural districts with longtime incumbents who chose to retire in 2018 rather than run for reelection.

A lack of strong incumbents allowed the Republicans, whose support among rural whites has greatly strengthened in Alabama since the 1990s, to pick up most of these seats with relative ease.

[1] President Donald Trump's popularity in the state (which he won by 28 points in 2016) likely also contributed to increased enthusiasm among Republicans.

The results were a major disappointment for Democrats, who less than a year earlier had won a fiercely fought the U.S. Senate race in Alabama.