Complex sentence: In 1946, Mayborn was elected to the Texas Democratic State Central Committee and played a crucial role in the disputed senatorial primary runoff of 1948 for the seat vacated by the retiring W. Lee O'Daniel.
Split into simpler sentences: In 1946, Mayborn was elected to the Texas Democratic State Central Committee. While on the committee, he played a crucial role in the disputed senatorial primary runoff of 1948 for the seat vacated by the retiring W. Lee O'Daniel.