When Brandi Carlile taped the "Austin City Limits" TV show in April, she got a chance to showcase her acclaimed new album "By the Way, I Forgive You" to 2,500 of her biggest fans. Saturday afternoon at ACL Fest, a crowd probably triple that size, maybe more, gathered at one of the festival's two largest stages for a show that featured a similar set and spirit, yet with one distinct difference.

An outspoken social activist, Carlile dove straight-on into the national news that has loomed large over the festival all weekend. Addressing "what we've done today to the Supreme Court," she referenced Saturday's confirmation vote of justice Brett Kavanaugh as she introduced "The Mother," an emotional song on her new album that deals with her recent entry into motherhood.

Carlile is married and gay, and when the same-sex couple had to fill out official documents for their young children, "I was forced to sign my kids' birth certificates in the father category." Same-sex couples have won significant victories in the courts in recent years, but "progress is not a one-way street," she cautioned. "We shouldn't think what we've done is final."

Urging everyone to vote in November, Carlile also played her recent hit "The Joke," introducing it as a song for "unloved, unaccepted, unnatural or illegal" citizens. For that song and most of the set, Carlile was backed by a stellar crew that included longtime bandmates Tim and Phil Hanseroth — twin brothers on guitar and bass, respectively — plus keyboards, drums and a three-piece string section.

While Carlile played, protesters of the Kavanaugh confirmation had gathered a few blocks away to block traffic on the Lamar Boulevard bridge, leading to 14 arrests. On a day when there was plenty to celebrate at Zilker Park, from radiant music to a dramatic Longhorn football victory, Carlile's gravitas served as a reminder that the world still awaits, just outside the gates.

A subsequent set on the nearby Barton Springs Stage from East Coast indie singer-songwriter Sharon Van Etten was a study in contrast, to some degree. Due to release her first new album in almost five years early next year, Van Etten showcased songs such as the lead single, "Comeback Kid," that suggest a turn toward more atmospheric rock. She also spoke very little to the crowd, pausing at one point to acknowledge her four-piece backing band and to thank people for showing up. The Barton Springs Stage wasn't packed, especially given the 6 p.m. hour of Van Etten's set, but it was a decent enough turnout for a set that felt like a primer to an upcoming tour after the album is released.