I am not familiar with these terms, but if by “war party” you mean Patriots fighting from independence from Great Britain and by “peace party” you mean Loyalists supporting Great Britain, then hopefully this helps :)
War Party/Patriots:
-felt they were being treated unfairly by the British
-did not want to be taxed without even being given the opportunity to have proper representation in government aka Parliament
-during the Boston Massacre, rowdy Patriots mocked British soldiers stationed in Boston. The British soldiers responded with gunfire, killing a few people. This attack further spurred on the Patriots’ desire for freedom.
Peace Party/Loyalists:
-believed there was no point in fighting against the mightiest nation w/ a big, trained militia who have the proper resources and experience to fight
-they felt that life would be better under England’s rule. Since they were already an established country, it would be simpler to just obey King George.
-the colonies would profit from trade w/ England
-believed the American colonies would be weak without the leadership and strength of Great Britain to guide them