Yep, my model is that OP does fund things that are explicitly bipartisan (like, they are not currently filtering on being actively affiliated with the left). My sense is in-practice it’s a fine balance and if there was some high-profile thing where Horizon became more associated with the right (like maybe some alumni becomes prominent in the republican party and very publicly credits Horizon for that, or there is some scandal involving someone on the right who is a Horizon alumni), then I do think their OP funding would have a decent chance of being jeopardized, and the same is not true on the left.
Another part of my model is that one of the key things about Horizon is that they are of a similar school of PR as OP themselves. They don’t make public statements. They try to look very professional. They are probably very happy to compromise on messaging and public comms with Open Phil and be responsive to almost any request that OP would have messaging wise. That makes up for a lot. I think if you had a more communicative and outspoken organization with a similar mission to Horizon, I think the funding situation would be a bunch dicier (though my guess is if they were competent, an organization like that could still get funding).
More broadly, I am not saying “OP staff want to only support organizations on the left”. My sense is that many individual OP staff would love to fund more organizations on the right, and would hate for polarization to occur, but that organizationally and because of constraints by Dustin, they can’t, and so you will see them fund organizations that aim for more engagement with the right, but there will be relatively hard lines and constraints that will mostly prevent that.
Habryka clarifies in a later comment: