Complex sentence: General Canby received conflicting orders from Washington as to whether to make peace or war on the Modocs, but war was not working, so the federal government authorized a peace commission and assigned Canby a key position on it.
Split into simpler sentences: General Canby received conflicting orders from Washington as to whether to make peace or war on the Modoc. As war was not working, the US government authorized a peace commission and assigned Canby a key position on it.