Here’s an interesting proof of the idea that America is still a young nation: Since we’re turning 250, anyone who’s 83 or older has been around for a full third of the official national story. These people are, we think, important witnesses to this fraught moment in our civic life — they have the baseline to judge the present against a past long enough to really see what’s special about right now. And when we asked a number of them for their views this spring, they did not hold back. Now, a caveat.