We the People of the United States, in Order to form a more perfect Union, establish Justice, insure domestic Tranquility, provide for the common defence, promote the general Welfare, and secure the Blessings of Liberty to ourselves and our Posterity, do ordain and establish this Constitution for the United States of America.
The preamble of U.S. Constitution provides a particularly striking example of the evolution of American English. In the sentence above, note the the ornate language, the unnecessary and irregular capitalization, and the British spelling of the word "defense."
If this many peculiarities appear in just the first sentence, imagine what else is buried in the rest of the document.
For one of the best (or worst, depending on your politics) examples of idiosyncratic language, see the Second Amendment, a statement so oddly written that our legal system is still wrangling over what it means. If you're looking for the ultimate example of why careful editing is important, the Second Amendment is it.
We've all seen how rapidly elements of the English language can change. Entire vocabularies of slang, for example, arise and die off in just a few short years. But it's still a shock to read the downright odd language of our own government's founding document. As Yogi Berra might say, the 1700s were a long time ago.