On this weekend's "Sunday Square Off," Democratic candidate for governor Steve Farley tells me how he'd wring $2 billion out of sales tax loopholes to help pay for Arizonans' schools, roads and health insurance.

Farley, a state senator from Tucson, is one of three Democrats running in next year's gubernatorial primary, the party's first since Janet Napolitano won the governor's race in 2002.

The two other candidates are David Garcia, an Arizona State University education professor who lost the 2014 race for school superintendent; and Noah Dyer, a marketing executive who switched his registration to Democrat for the first time late last year.

Also on "Square Off," the roundtable of Catherine Alonzo, chief executive officer of Javelina, marketing & political consulting firm; Jon Gabriel, editor-in-chief of Ricochet.com and co-host of "The Conservatarian" podcast; and political analyst Chris Herstam discuss:

• The aftermath of last week's shootings at congressional Republicans' baseball practice: How Arizona's members of Congress responded and what the Gabby Giffords shooting six years ago tells us about whether anything will change in Congress.

• Why President Trump would want to hire Cindy McCain, wife of his political enemy John McCain, and why she would want the job.

• What Trump's latest change in immigration policy could mean for the Dreamers.

"Sunday Square Off" airs at 8 a.m. Sundays, after NBC's "Meet the Press."