Methuselah’s children by Robert A. Heinlein

After the fall of the American Ayatollahs as foretold in Stranger in a Strange Land and chronicled in Revolt in 2100, the United States of America at last fulfills the promise inherent in its first Revolution: for the first time in human history there is a nation with Liberty and Justice for All.
No one may seize or harm the person or property of another, or invade his privacy, or force him to do his bidding. Americans are fiercely proud of their re-won liberties and the blood it cost them: nothing could make them forswear those truths they hold self-evident. Nothing except the promise of immortality…