About 100 days into Joe Biden's presidency, he addressed a joint session of Congress. In it, he said, "America is an idea — unique in the world. We are all created equal. It’s who we are. We cannot walk away from that principle." During Reagan's presidency, he said, "America is less a place than an idea."
If we want to understand what that idea is, we need to look at the founding of the country. At the statements we immortalized in our constitution that were beyond our then-present state of being. (And arguably still beyond our state of being.)