Complex sentence: The U.S. peace commission bargained in bad faith with the Lakota and Northern Cheyenne, offering annuities to alleviate near-starvation, but keeping secret the plan to build forts along the Bozeman Trail.
Split into simpler sentences: The U.S. peace commission bargained in bad faith with the Lakota and Northern Cheyenne. They offered annuities to alleviate near-starvation, but kept secret the US plans to build forts along the Bozeman Trail.