Was the United States justified in their reasoning for seeking independence from Great Britain?

Great Britain was taxing the citizens for not a very good reason

Although England has many reasons as to why the colonies were unjustified in waging a war, the colonists still were justified because the “Declaration of Independence” clearly stated the colonist's problems against the king. They said that they were breaking away from England to become The United States of America

the  wilmot proviso  was designed to eliminate  slavery  within the  landacquired as a result of the mexican war (1846-48). fearing the addition of a pro-slave territory, pennsylvania congressman david  wilmot proposedhis amendment to the bill.