I’ve either been involved in or keeping an eye on American politics for more than 60 years now. We’ve faced plenty of tough questions during that time, and though many of them have been resolved and we’ve moved on, some are tenacious — income inequality, racial equity, the ever-ballooning national deficit, climate change. But in all those years, the question I’ve found myself returning to again and again — and that I suppose we’ll never really resolve — is the one Lincoln posed at Gettysburg: Can a nation like ours, ‘conceived in Liberty, and dedicated to the proposition that all men are created equal,’ endure?