The idea is that it gives moderate republicans a path to voting for her.

Without the endorsements, they would feel like they’re betraying their principles and their party to vote D. With them, they can make a choice: Lots of rank and file voters will stick with Trump, but if a few party leaders, recently respected within the party, can vote for Harris, maybe that isn’t such a betrayal after all.

Will it change the vote by 5-10%? Basically zero chance of that. But if it swings a few thousand voters in some strategic areas, it can make a difference. It’s not a strategy aimed at very many people, but those votes on the margins matter.