In her first interview as Phoenix mayor, Kate Gallego joins “Sunday Square Off” to discuss the raft of challenges facing her as she takes office, and the line-of-duty death of a Phoenix cop just minutes before she was sworn in last week.

The feds have dropped off hundreds of asylum seekers in Phoenix. Faith groups and volunteers are calling on the city to help manage the crisis. Will new Mayor Kate Gallego lend a hand?

Looking ahead to the 2020 elections, “Sunday Square Off” moderator Brahm Resnik asks Gallego whether she’ll endorse a candidate in the Democratic primary for the U.S. Senate, which could include her former husband, Congressman Ruben Gallego of Phoenix.

Also on “Square Off,” New York Times best-selling author Evan Thomas discusses “First,” his new biography of Justice Sandra Day O’Connor.

Thomas takes us back to O'Connor's youth on a vast family ranch in the southeastern corner of Arizona. 

Thomas shows us how that helped propel her to the highest court in the land - as the first woman on the U.S. Supreme Court and a trailblazer for others. 

We also discuss O'Connor's role as the swing vote in more than 300 court decisions, including Bush v Gore in 2000, which decided the presidential race.

“Sunday Square Off” airs at 8 a.m. Sundays on 12 News, after NBC’s “Meet the Press” with Chuck Todd.