When athletes march out at the opening ceremony of next month's Winter Olympics in Pyeongchang, North and South Koreans will do so under a single flag. Many hope this signals a thaw in tensions between the two nations — and with the U.S. But others are not so optimistic. | Want to support 1A? Subscribe to our podcast and give to your local public radio station at donate.npr.org/1A. Email the show at 1a@wamu.org.