Complex sentence: He rejected the SDUSA (majority Socialist Party) position on the Vietnam War, which demanded an end to bombings and a negotiated peace settlement, and he called rather for an immediate cease fire and immediate withdrawal of U.S. forces from Vietnam.
Split into simpler sentences: He rejected the SDUSA (majority Socialist Party) position on the Vietnam War, which demanded an end to bombings and a negotiated peace settlement. Harrington called rather for an immediate cease fire and immediate withdrawal of U.S. forces from Vietnam.