I don't understand which decades are in question, since Ukraine has only been independent for about 3 of them. Ukraine entered a partnership with NATO in 1994 (mirroring a similar partnership with CIS), and the US has been palpably hesitant to advance their formal military commitment beyond that level.
This is of course in contrast to annexation of Crimea and the Donbas.
I'm referring to the actions of the State Department in Ukraine, as evidenced by "Cablegate" and by later reporting and leaks regarding the Maiden revolution and subsequent elections. I'm sure HN will be full of experts within a few hours, if the speed of new armchair virologists the last few years are any indication.
This is of course in contrast to annexation of Crimea and the Donbas.