Speaking as someone who has had a lot to do with these issues, I can tell you that whoever winds up culpable for this has purchased tickets to hell for all they can pay, sort of. First of all, it is an ad, not journalism. Snagging a photo you don't own for an ad is indefensible from any fair use standpoint. Regarding copyright, it exists the instant a photo is made, no claims or registration are necessary to enforce copyright, registration simply helps establish ownership in the event of a dispute. There will be little to dispute since the ad crafter did not originate the photograph nor seek to or posses releases from the subjects (separate but relevant, and also actionable). The hardest part will be actually extracting the money from a political organization, since they are notorious for being financially unreliable, even for things they have contracted for. They are around till election day, and then "poof". It's doubtful that a defendant or representative will even bother show up to court, and good luck finding someone to collect from.
Politicals are always cash on the barrelhead with me, no exceptions.