Many countries similarly mythologize their founding, as part of their religion of nationalism. American nationalism is especially powerful because Americans can interpret their historical triumphs as signs of their “manifest destiny.” However, this theological interpretation of American history and politics, which primes Americans for plutocracy, derives mainly from Christianity. The secular humanistic, Enlightenment ideas that founded the US entail not self-worship but humility and even something like the darker outlook of Schopenhauer.
We should be optimistic about our secular freedom to create and to progress, but only within the larger pessimism about everything that happens within godless nature. That’s the balanced view that can make Americans proud of their accomplishments, but not at the cost of exchanging archaic Christianity with xenophobic, triumphalist nationalism. To the extent that Americans effectively worship their founders and wealthy rulers, the worship is explicitly or implicitly theistic. The secular alternative shouldn’t be naively idealistic even about human potential.