She’s taking on the most powerful company in Arizona - and she’s winning.

On this weekend’s “Sunday Square Off,” Stacey Champion yells us how she figured out she could challenge the rate increase Arizona Public Service got two years ago and the utility watchdogs who approved it.

Champion’s challenge isn’t done yet, but she’s gone much further than most had thought possible in questioning new rates that even the power company concedes are hard for customers to understand.

Also on this weekend’s “Square Off”:

Unanswered questions after police-shooting report

A $150,000 study of Phoenix's record number of police shootings last year reaches no firm conclusions about why it happened. Viridiana Hernandez, of Maryvale-based Poder in Action, was one of the few community members who met with the study researchers. She tells us why she believes shootings spiked.

Why did AZGOP chair put party behind tax increase?

The week’s political questions: Why did Kelli Ward plant the Arizona Republican Party firmly behind a tax increase? When will Sen. Kyrsten Sinema share her thoughts on the Mueller report? Will Congressman Greg Stanton enjoy his front-row seat at House hearings digging deeper into the Mueller report? And on the one-year anniversary of the #RedForEd teachers strike, what will organizers do for an encore this year?

One year after strike, what’s #RedForEd’s next move?

We’re joined by Laurie Roberts, columnist for the Arizona Republic, and Chris Baker, Republican consultant at Blue Point Consulting.

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