Declaration of Independence foundational to all US Law Proof thereof
What few Americans on either side of the ideological aisle know is that YES, the Declaration of Independence IS a part of our laws. In fact, you will find in the United States Code (our nation’s law database). Our nation’s organic laws are listed first, and the Declaration of Independence is first among them. It doesn’t get much more foundational than that (except perhaps the Bible, which is the document from which the founders gained the understanding that “all men are created equal, that they are endowed by their Creator with certain unalienable Rights”).

As important as this fact is, this is not the only proof that if we are under the United States Constitution (and we are, despite the loathing of the Left), we are also under the Declaration of Independence. As Barton and Green discussed on Wallbuilders Live:

1. Article VII of the U.S. Constitution dates itself not only based on the Christian calendar (“in the Year of our Lord one thousand seven hundred and Eighty seven“–icky to Leftists dedicated to the fantasy of government divorced from God) but dates itself back to the Declaration of Independence:
“done in Convention by the Unanimous Consent of the States present the Seventeenth Day of September in the Year of our Lord one thousand seven hundred and Eighty seven and of the Independence of the United States of America the Twelfth“
Presidential acts (even those signed by President Barack Obama, who loathes our nation’s foundation like no president before him) are still to this day dated “in the Year of our Lord” as well as the year of our nation’s independence.
The enabling acts of the states testify to this. Enabling acts are the acts by which territories became states, and they set forth the conditions under which a territory may become a state. States are required constitutionally to implement a republican form of government (sorry, no dictatorships, politburos or oligarchies allowed). Their form of government also “shall not be repugnant to the Constitution of the United States and the principles of the Declaration of Independence.” Notice that the states are required to be in compliance with not only the U.S. Constitution, but the Declaration of Independence. Examples: Arizona, Nevada, South Dakota.
The U.S. Constitution cannot be understood without the Declaration of Independence. In other words, many key parts of the U.S. Constitution are corollaries (i.e. they answer) to the grievances or problems brought up in the Declaration of Independence.
Article 1 Section 5 where it says “Neither House, during the Session of Congress, shall, without the Consent of the other, adjourn for more than three days, nor to any other Place than that in which the two Houses shall be sitting,” this cures or answers the fourth problem or grievance raised in the Declaration of Independence which said: “He has called together legislative bodies at places unusual, uncomfortable, and distant from the depository of their public Records, for the sole purpose of fatiguing them into compliance with his measures.” In other words, why does our constitution do what it does? Because of the problems (or abuses against our God-given rights endowed upon us by the aforementioned Creator) identified in the Declaration. You cannot understand the meaning and intent of the Constitution without the context of the Declaration.
Grievance 5 and 6 of the Declaration are answered by Article 1 Section 4 of the Constitution
Grievance 7 of the Declaration is resolved by Article 1 Section 8 paragraph 4
Grievance 8 of the Declaration is answered by Article 1 Section 8 paragraph 9.

So since the Declaration of Independence is the original source document from which all other U.S. laws (including the Constitution) get their authority, from where does the Declaration get its authority? Remember, it already told us: The Laws of Nature and of Nature’s God (sorry, God-haters).