LAST RESORT?

President Trump’s attorney general nominee, William Barr, told a Senate panel Tuesday that he “can conceive of situations” where the Justice Department might jail reporters. Barr made the worrisome remark in response to a question from Senator Amy Klobuchar (D-MN) who asked Barr, “If you’re confirmed, will the Justice Department jail reporters for doing their jobs?” Barr reportedly did not give a direct answer, but finished his response by stating that prosecuting reporters would be a “last resort” that could happen, especially if a news outlet has run through a “red flag.”

https://www.thedailybeast.com/william-barr-i-can-conceive-of-situations-where-journalists-might-be-jailed-as-last-resort

What does “run through a red flag” mean?

Cross a red line?

Perpetrate a FF?

Seems like odd verbiage.