Identify what each document was intended to do and when it was adopted or signed. Do not treat a declaration of principles, a governmental framework, and the actual distribution of rights as identical.
Worked example
A statement announcing a break from a ruler is different from a document organizing a new government. Both can matter without serving the same purpose.
Two Documents, Different Tasks
The Declaration of Independence was adopted in 1776. It announced separation from Britain and set out reasons and principles. The Constitution was signed in 1787 and proposed a federal governmental framework; state ratification followed. Slavery and exclusion from political participation persisted, so statements of ideals must be compared with laws and lived experiences.