Why did John Adams believe the soldiers in the Boston Massacre were innocent?

“The Part I took in Defence of Cptn. Preston and the Soldiers, procured me Anxiety, and Obloquy enough. It was, however, one of the most gallant, generous, manly and disinterested Actions of my whole Life, and one of the best Pieces of Service I ever rendered my Country. Judgment of Death against those Soldiers would have been as foul a Stain upon this Country as the Executions of the Quakers or Witches, anciently. As the...

“The Part I took in Defence of Cptn. Preston and the Soldiers, procured me Anxiety, and Obloquy enough. It was, however, one of the most gallant, generous, manly and disinterested Actions of my whole Life, and one of the best Pieces of Service I ever rendered my Country. Judgment of Death against those Soldiers would have been as foul a Stain upon this Country as the Executions of the Quakers or Witches, anciently. As the Evidence was, the Verdict of the Jury was exactly right.”   –John Adams

John Adams decided to defend the soldiers and commander of the troops in the Boston Massacre.  He did so at a time when tensions were high in Massachusetts and political fallout was very possible.  As a lawyer, it is not your job to judge guilt or innocence about your clients.  The duty of the attorney is to ensure that clients are given a solid defense.  What can be said about Adam's defense of the British soldiers is that it was very effective.  In the case of the commander, Thomas Gage, Adams and his legal team were able to prove reasonable doubt about whether he was the man that yelled "fire" to his troops.  Adams believed that members of the mob may have yelled the command which resulted in the deaths of American colonists.  In the case of the soldiers, Adams painted a scene of chaos and violence in which the troops had to fight for their lives.  Adams believed that it was the right of the British soldiers to defend themselves from imminent bodily harm or even death.