Hard decisions deserve hard questions, climate change most of all. For me, this was the best question:

5. Just how rich are those future generations likely to be? If you expect economic growth to continue at the average annual rate of 2.3 percent, to which we've grown accustomed, then in 400 years, the average American will have an income of more than $1 million per day—and that's in the equivalent of today's dollars (i.e., after correcting for inflation). Does it really make sense for you and me to sacrifice for the benefit of those future gazillionaires?

Which is why I'm pro-growth first of all. Compound interest is your friend!