Ukraine should declare that they're withdrawing from the Lisbon Protocol, and will start working towards creation/procurement of nuclear weapons. Ukraine, Kazakhstan, and Belaruse agreed to give up their nuclear weapons, in exchange for guarantees on their border security, secured by the US and Russia. Since Russia has reneged, and the US appears to be doing the same, maybe Ukraine could bolster the "cards in their hand" by looking towards rearming. While I hate the idea of another nuclear power, Ukraine was the #3 nuclear power, between separation from the USSR and the 1992 Lisbon Protocol. Maybe their next strategic move should be to fail, like the US and Russia have.
I understand Russian concerns - Gorbachev was told, when the Berlin Wall came down, that NATO would not expand towards the Russian Border. That promise was not ratified by NATO, but was a part of the decision making process, as it was a Russian concern. NATO has expanded 12 times since then, towards the Russian Border. As mad as they might be, the answer is not to simply take back lands they gave up.
The same goes for the US. A few decades passing by, is no excuse to simply decide to not honor obligations previously entered into.
But, if everybody is just changing their minds, and simply "doing whatever we want" is on the table, I'm sure, since Ukraine supplied much of the Cold War hardware and expertise to the USSR, that manufacturing and knowledge base is still there, at least to some degree.
They probably wouldn't have to do it....mentioning the interest as a strategic consideration could be the kick in the ass needed, to help the Lisbon Protocol participants to remember their roles in the guarantees made, on the condition of giving up those nukes.
First you break government. Once broken, privatize everything on the justification of government not working.
Use propaganda to make people hateful and violent towards election workers. Use to loss of election workers to either have the incumbent administration run elections with "impartiality" or cancel elections altogether.
Cut government funding and make everything unpredictable, causing farmers and business owners to go bankrupt. Have oligarchs buy up everything at rock-bottom pricing, and turn the citizens back into serfs, who will be poor enough to shut up and do as they're told.