What was Jameson’s defense strategy? How did this defense challenge the system of slavery?

In his book, Celia, A Slave, Melton McLaurin notes that Judge Hall wanted a speedy, by-the-book trial, and that the [c]ouncil for the defense . . .was not cooperating with the judge’s wishes. Why did Judge Hall choose John Jameson for Celia’s defense? McLaurin asserts that Jameson’s defense of Celia was more radical than the celebrated Dred Scott case. What was Jameson’s defense strategy? How did this defense challenge the system of slavery? The issues of 1850s Missouri should form part of your answer.