Final answer:
The king's refusal to assent to necessary laws violated the founding principle of unalienable rights, which are inherent and cannot be taken away, thus justifying the colonists' pursuit of independence and a new government that upholds these rights.
Step-by-step explanation:
The grievance stated in the Declaration of Independence, 'He has refused his Assent to Laws, the most wholesome and necessary for the public good,' directly relates to the founding principle of unalienable rights. This principle is grounded in the belief that individuals are born with certain rights that cannot be taken away or denied. The king's refusal to assent to laws that were beneficial for the public good was seen as a violation of these rights, particularly the rights to Life, Liberty, and the pursuit of Happiness. By denying assent, the king was impeding the function of a government that is meant to secure and protect these unalienable rights. Therefore, such actions justified the colonists' decision to seek independence and to form a government that would be more likely to safeguard their unalienable rights and overall wellbeing.