Ukraine should have been given NATO membership, OR at least NATO protection way back when they were forced to give up their nukes. I say it was a mistake that putin took advantage of.

I don't disagree with this. They should have either kept the nukes or gotten guarenteed protection like a NATO membership they were given a horrible deal by getting neither.

But the right thing to do currently, and something I do think Harris and/or Biden would have done or worked towards (undermining internal US politics not taken in account) is put a permanent American security force inside Ukraine, including naval bases.

I don't think Harris would have done this at all. I don't think a single troop would have gone there in a non weapons training capacity if she were the president. I think she would have kept on sending weapons and that's about it, and, there's a decent chance a end of hostilties a peace deal whatever you want to call it would have happened under her in the next four years if Trump lost as I personally don't believe this conflict has 4 years left in it, regardless of who the president is.