Complex sentence: The union struggles of the 1930s were set against a larger backdrop of economic calamity from which the SIU was born, including the Great Depression in the United States, as well as a worldwide economic slump.
Split into simpler sentences: The union struggles of the 1930s were set against a larger backdrop of economic calamity. The unsettled times from which the SIU emerged included the Great Depression in the United States, as well as a worldwide economic slump.