As Americans took to social media to post pictures of bare shelves, we learned that Transportation Secy Pete Buttigieg has been on tax paid paternity leave since August. He got the job as a reward for dropping out of the presidential race and throwing his support to Joe Biden — and because he likes trains, having gotten engaged at a train station. When the country is having supply-chain problems, the transportation secretary’s skills and experience, let alone availability, become rather, uh, indispensable. The public didn’t even learn about Buttigieg’s break at the start, but only after transportation-related problems exploded around...