Complex sentence: After a long primary battle, Hoynes lost the nomination to New Hampshire Governor Josiah Bartlet, with his campaign beginning to lose momentum when Josh Lyman, his chief strategist, defected to the Bartlet operation.
Split into simpler sentences: After a long primary battle, Hoynes lost the nomination to New Hampshire Governor Josiah Bartlet. Incidentally, he started losing momentum in that campaign exactly when Josh Lyman, his chief strategist, defected to the Bartlet operation.