"Why, exactly, did you come up with this thread?"
Draugnar made a comment about it in the "Men Are Second-Class Citizens" thread, CA.
I said (in many, many more words, of course) that saying men are second-class citizens in the US is as absurd as saying there's a War on Christianity in the most Christian Western nation where 70-80% of the population is Christian and 80-90% of its leaders in Congress, the White House and Supreme Court are Christian.
He said something along the lines of "numbers don't mean there isn't a war" and as an example cited that a tiny group of people declared war on the US by ramming planes into the World Trade Center.
So here we are.
"the Declaration has been considered our Founding Document for many decades, and I think most Americans would heartily disagree with you."
Well, we considered blacks 3/5th of a person for nearly the first century of our existence...that didn't mean that assertion was right or true.
And I think the point still stands--it dissolves ties with Great Britain but does NOT establish the United States of America...
Partly because they weren't so sure they wanted to be united yet, partly because no one knew how that might look or function yet, and partly because, hey, they had to win what was a pretty dire-looking war first, one in which they lost New York and Philadelphia.
So I'd relate that back to your point, CA:
"I think it's pretty much official that 1776 is considered the birth of our nation."
I again make that distinction as I did above between cutting the cord and being truly born in the sense of becoming a person (dare I say born again? ...No.) ;)
You're not really "you" yet the second you're born...you have no personality established yet...even if there's elements coded into you, they haven't been expressed yet...
It takes a few years before you grow up into a toddler and have a mind of your own (a toddler mind that thinks you, too, are oh-so-independent!) ;)
So that's the distinction I'd draw--even if you want to say that the Thirteen Colonies were born as a nation 1776, they weren't the UNITED STATES of America until 1787, and that's the country we are and the one we're talking about now.
As a final point--I think the above argument stands, but even if we did want to consider the Declaration a founding document...
Well, again, technically so were the Articles of Confederation, and the 3/5th compromise in the Constitution, for that matter--and they're no longer applicable.
Further, again, the ONLY reference we get to a deity is the Jeffersonian ideal of a "Creator" as mentioned in the Constitution...and as I've outlined above, Jefferson was no fan of religious scripture, especially books important to the New Testament (ie, Revelations) so between that and Jefferson's being a deist, I don't think you can classify the "Creator" example in the Declaration of Independence as being Christian when, well, its author was notoriously anti-Christian, at least in a religious respect.
I'd add as a final point that if we DID want to accept the Declaration as a founding document...
How about we go back a bit earlier and accept "Common Sense" by Thomas Paine as one as well--after all, it's widely credited with turning a quarrel with the home nation into a full-blown movement for revolution...pretty foundational along those lines...
And as Paine was a NOTORIOUS deist and anti-Christian, dedicating an entire book--"The Age of Reason"--to attacking the Judeo-Christian mythos...
Well, again, our foundations aren't as "Christian" as they may seem at first glance. ;)