Did Grant's decision not to entrench depend on whether Johnston, rather than a different general, would attack?
Short answerYes, in this interpretation. Johnston's aggression and worsening numerical position made an early attack especially likely.
NotesThe proposed explanation for Grant's camp depended on the commander facing him. Johnston was capable, confident, and aggressive, while approaching Union reinforcements gave him a reason to attack quickly. With roughly 40,000 men against Grant's approximately 45,000 and another Union army approaching, he needed to defeat the opposing armies separately. In this interpretation, Grant could reasonably expect Johnston to take the risk of attacking.