I do not have to prove any such thing.
Yes, you do. It is your assertion, therefore you have the burden to prove it. Until then, there is no logical means to object to an atheist claiming their "God-given" rights.
One key cornerstone to our foundation as a nation is our Declaration of Independence.
This is the recourse of a desperate mind who cannot justify their position themselves.
Do you really wish to start chipping away at that fine document to prove a point and take a chance on eroding everything else that follows?
If you knew anything about the Declaration of Independence, you'd know that the defining elements of the document are the list of grievances. Of course, if you really insist on cherry picking snippets and applying them out of context, we could move on to the people of the United States pledging their fortunes to each other.
Or isn't it better to just take it's word for it and base our system on the FACT that our most basic human rights are not given to us by the government.....that it is merely their duly elected duty to help protect these rights.
Yeah, that's proof positive that God exists.

What an incredibly stupid thing to say, that was.