Complex sentence: Since the early 1980s the League and affiliates have also organized mobilizations against Nazis and the Ku Klux Klan; in the late-1980s it was an early campaigner to save Mumia Abu-Jamal from death row.
Split into simpler sentences: Since the early 1980s the League and affiliates have also organized mobilizations against Nazis and the Ku Klux Klan. They were an early campaigner to save Mumia Abu-Jamal from death row.