Use 'tractable' when people behave in a cooperative way that allows guidance. The new policy was introduced to a tractable audience.
Pro Tip 2/3
Negative Connotation
'Tractable' might imply a lack of independence or resistance, sometimes seen as a negative. She was so tractable that her friends made all her choices for her.
Pro Tip 3/3
Subtle Control
Implies control without force or confrontation, often through persuasion or influence. The mediator found the group to be tractable and steered them to agreement.