I'm going to dive right in and start the posting with a bold claim: America does not have a written Constitution; at least, not a binding one. (A disclaimer: this post is a part re-post, part clarification of a claim I made on The Economist's Democracy in America blog.)
The US Constitution has been so broadly interpreted, and carries with it so much precedent and case law, that its actual words are nearly meaningless. We have a relatively firm understanding of what's constitutional and what isn't, but that understanding is informed more by unwritten social values and written case law than by the Constitution itself. I think I'll jokingly refer to this as the Dead Constitution theory.
Some examples are in order. There are some cases that could be argued both ways (does confessional privilege run counter to or in agreement with the First Amendment?), but other cases seem clearer.
- The federal government is involved in education; I haven't heard any grumblings that it shouldn't be (and I wouldn't put forth those grumblings, myself). But I don't know of any text in the Constitution that allows this, and the Tenth Amendment would therefore seem to disallow it.
- Roe v Wade famously hinges on a Constitutional right to privacy. That right isn't in the written Constitution, though I'd argue it's firmly in our unwritten one.
- The secret trials and "indefinite detention" of Guantanamo prisoners seem to go against the Sixth Amendment, given the Supreme Court's ruling that Guantanamo prisoners fall under the Constitution's jurisdiction.
- The text "In God We Trust" on coins — to say nothing of the many benedictions I had to endure as part of my public high school's marching band on public holidays — are an establishment of religion, even if they're not an establishment of a specific religion.
When the written and unwritten constitutions are in agreement, we refer to the written document by way of convenience (i.e., "that's protected by the First Amendment"). Where they differ, the unwritten one trumps.
I especially welcome our resident legal expert's input.