Complex sentence: Prohibition remained a major reform movement from the 1840s until 1920, when nationwide prohibition went into effect, and was supported by evangelical Protestant churches, especially the Methodists, Baptists, Presbyterians, Disciples of Christ, and Congregationalists.
Split into simpler sentences: Prohibition remained a major reform movement from the 1840s until 1920, when nationwide prohibition went into effect. The movement was supported by evangelical Protestant churches, especially the Methodists, Baptists, Presbyterians, Disciples of Christ, and Congregationalists.