Though I will point out civil servants in the position to decide such things are practically unfierable and that politicians’ public persona are down-stream from public opinion, if the media and academia that are mostly upstream decide open borders really is a moral crime akin to segregation (not hard since it fundamentally is segregation—not that I think this in itself makes it immoral), then public opinion would try to resist by a few populist politicians but would eventually succumb like it has on all other issues where its interests or opinions were pitted against the former.
Good counter-argument, updated
Though I will point out civil servants in the position to decide such things are practically unfierable and that politicians’ public persona are down-stream from public opinion, if the media and academia that are mostly upstream decide open borders really is a moral crime akin to segregation (not hard since it fundamentally is segregation—not that I think this in itself makes it immoral), then public opinion would try to resist by a few populist politicians but would eventually succumb like it has on all other issues where its interests or opinions were pitted against the former.