Just a couple of months ago, someone was still suing[1] to block Alaska Air/Hawaiian. This is a merger that already entirely went through. I would predict equal likelihood of some state lawsuit derailing a merger like this.

[1] https://viewfromthewing.com/passengers-demand-court-undo-ala...

There's a pretty clear difference between a lawsuit by 8 individuals, vs one filed by attorneys general representing a combined ~100m people.