I agree Paul Krugman is a expert in economics.
I don't. When someone has called for a real estate bubble as a remedy for the dot-com bubble, suggested that an alien invasion would help the economy, and now calls for fucking up relations with one of our country's biggest trading partners, I'd have to say he has disqualified himself as an economist quite thoroughly. He may have had some clever observations to make about world trade once upon a time, but today he is no economist at all. He is a court astrologer, and nothing more.