Primaries 2018: 3 Key Takeaways From Tuesday Night

FILE — Mary Gay Scanlon, a Democrat running for the U.S. House, at a campaign event in Folcroft, Pa., May 7, 2018. In primaries held on May 15, Democrats in four congressional districts ringing Philadelphia selected female nominees; the area has emerged as one of the most important battlegrounds in the 2018 election. (Michelle Gustafson/The New York Times)