It goes something like this: "Politicians use economics the way a drunk uses a lamppost: for support, not illumination." It's what Princeton economist Alan Blinder is exploring in his new book: Why can't economists and lawmakers seem to understand each other? First though: The Department of Commerce says it's going to ask people about their citizenship in 2020. Several states are suing, and critics say it could keep some folks from talking to census takers. Today we'll look at the potential consequences of undercounting. Plus: Mark Zuckerberg said he'd testify before Congress about the Cambridge Analyitica scandal, but he doesn't plan to talk to the United Kingdom Parliament. We'll look at the European perspective on Facebook's latest controversy.