The election for mayor of Frisco, Texas, became a referendum on diversity and a test of anti-Muslim messaging in a general election contest.

© Desiree Rios for The New York Times

Four candidates running in a historically Black district risk dividing the Black vote and losing to Ms. Wasserman Schultz, who is white.

© Eric Lee/The New York Times

Mr. Trump backed Mr. Collins over Derek Dooley, a former football coach supported by Gov. Brian Kemp, a Republican whose relationship with the president is strained.

© Audra Melton for The New York Times

A review of polling data shows an extraordinary swing among white working-class voters on the president’s handling of the economy.

© Haiyun Jiang/The New York Times