I think you got that wrong enough it warrants a correction…
They gave them up for assurances that Russia and the USA would protect them if they were attacked.
Edit: that’s why the USA is giving them weapons, they’re honoring the deal, or at least trying to, not 100% sure on specifics, I’m sure it was vague on what protecting them would entail.
wiki says
what assistance would that not be if not protecting them in some way or another?