"In order to [adequately address climate change], you know, even to send a signal to the world, most experts believe the important thing is that the United States get its house in order," Mr. Zakaria said Sunday. "And to really tackle the climate crisis and to really take on the, you know, because carbon is produced in so many different ways — and cement and steel and plastics. It's much more than just the burning of fuel for transport. You need a carbon tax. Do you think that the United States could do that? That is the simplest price signal that will change, slowly but surely, change the economy. Can we do it?"