Samuel Worcester/Indian Removal Act question

Oct 2014
New York
I have to cross examine Samuel Worcester in a mock trial against Andrew Jackson. Jackson is being charged for crimes against humanity in signing the Indian Removal Act. I know he was influential in defending the Cherokee nation but I have no idea how the prosecution is going to use him. Could anyone who knows a lot about the Indian Removal Act and Samuel Worcester help me? Are there any things that would disprove his reliability as a witness? I know this is a mock trial question but I figured the best place to go would be a history forum. Thanks