Historian Bernard Sheehan argues that Jefferson believed that assimilation was best for American Indians; second best was removal to the west. He felt that the worst outcome of the cultural and resources conflict between American citizens and American Indians would be their attacking the whites. Jefferson told Secretary of War General Henry Dearborn (Indian affairs were then under the War Department), "If we are constrained to lift the hatchet against any tribe, we will never lay it down until that tribe is exterminated or driven beyond the Mississippi." Miller agrees that Jefferson believed that Indians should assimilate to American customs and agriculture. Historians such as Peter S. Onuf and Merrill D. Peterson argue that Jefferson's actual Indian policies did little to promote assimilation and were a pretext to seize lands.