The Declaration sets principles behind a just and fair government, the Constitution outlines how this just government would function (it would function lawfully). When the government doesn't follow the principles and doesn't apply the required due process when it needs to be applied, it gets outisde the notion of a just government. The right to the current actions lies in the Constitution itself, as it doesn't allow for the current government to exist in its current form (doesn't function lawfully), and it doesn't fit the notion of a just government.