I don’t think it would even have to go that far.
It’s mostly that Harris needs to be able to present credible red lines. Right now, the perception is that Israel can get away with absolutely anything.
Anything to break that perception it might be enough. A light version might be something like, “Every time X happens, we’ll delay weapons shipments by a week while we investigate.” That’s not much and it might not even change Israel’s behavior but I suspect that just articulating some policy and sticking to it would be sufficient.
That’s inherent to the idea of theft. We judge thieves based on their thefts.
It’s irrelevant if they also happen to have a bunch of stuff they didn’t steal.
A few stolen artifacts corrupt the legitimacy of the entire exhibit.