'Blue Bloods' Season 12 Finale: Erin Reagan's 'Big Swing,' Explained

The "will-they-won't-they" of Blue Bloods Season 12 wasn't a romance but involved A.D.A. Erin Reagan's internal debate about running for district attorney. During Friday's season finale, "Silver Linings," Erin (Bridget Moynahan) finally committed to running after Commissioner Frank Reagan's feud with D.A. Kimberly Crawford reached a boiling point. The "big swing" sets up the major storylines for the upcoming Season 13, showrunner Kevin Wade explained in a post-show interview with Deadline.

Throughout Season 12, Erin toyed with the idea of running for higher office, especially as it became clear she didn't have much chemistry with Crawford (Roslyn Ruff). In "Silver Linings," Frank (Tom Selleck) publicly complained about Crawford's modernizing tactics, including changing charging guidelines and changing the definition of "non-violent crimes." Frank even wanted Crawford's A.D.A.s to publicly speak out against their boss. This made it impossible for Crawford and Erin to work together and likely pushed her over the edge. Although Erin is afraid to lose, she told her family that their love and support would make her "unbeatable."

(Photo: CBS)

Erin has been an A.D.A. on Blue Bloods since the show began over a decade ago now, working under multiple D.A.s who she has often disagreed with. "For her character, the choice seemed to be: if you think you can do the job, then ask for it or otherwise, sit back down," Wade told Deadline when asked why Erin is running now. "Time's come for her to ask for it by announcing she's running for the office."

The upcoming Season 13 will have "two tracks" for Erin, Wade explained. "Doing the job she has, and challenging herself and being challenged about her fitness for the job she wants," he said. "And what she's willing, and not willing, to do in order to get it. So plenty of horse-trading, soul-searching, and disruption with the powers that be, her partner Anthony, and especially her family."

CBS picked up Blue Bloods for a 13th season on April 26, so fans will not have to spend the summer campaigning for the show. The series remains the most-viewed show on Friday nights, averaging 9.81 million viewers during the season. It is also the fourth-most watched broadcast series. The show passed its 250th episode milestone during Season 12. Past episodes are available to stream on Paramount+.