If you’re not familiar, in the gut-and-amend process legislators entirely delete the contents of a bill and insert an entirely different bill. They do this to avoid procedural deadlines or to shield a controversial bill from having to go through committee hearings or budget analysis.
For instance, in the California legislature there is a “cross-over” deadline in May, meaning that a bill has to pass its house of origin (Assembly or Senate) by that date or it is dead for the session. But bills can be amended - significantly - and just continue through the legislative process.
This often happens late in the session, with little notice to those who will be voting on the bill, and next to no opportunity for public comment.
Last year this tactic was used with devastating effect in a number of Gunpocalypse bills.
This year, it was used in the opposite direction - to gut-and-amend AB 149, a pro-gun bill that dealt with informing gun owners on trial that their eligibility to possess a firearm could be in jeopardy if accepted a plea deal or pled guilty, into a bill providing taxpayers the opportunity to contribute to Habitat for Humanity on their tax returns.
Yes, you read that correctly. They took a bill having to do with the criminal justice system and changed it into something completely different.
Despite all efforts at reform, and any efforts pro-Second Amendment organizations make to pass a pro-gun bill, that bill can still be changed on a whim of the author or majority party into something completely different.