Even if we conceded the utility of collapsing the US from four time zones to two, the Atlantic writer's proposal would certainly not be the way to go. One desirable characteristic of setting time zone boundaries is to minimize the difference, whether positive or negative, between the clock and solar time. If it didn't matter, she might as well have picked any two random zones in the world. She clearly is aware of that principle, but she blew it in the application. As her proposal stands, Central and Eastern would always observe Eastern. Okay. But Pacific and Mountain would observe Central! Think about it. Central does not get to observe its own true time, while two other time zones do observe it, with one of those having a two-hour offset! The obvious solution is this: Pacific and Mountain observe Mountain. Central and Eastern observer Central. Now you would be using the two time zones most central to the country, with no zone offset more than an hour from solar. And two of them would have no offset.