Russian invasion of Ukraine
In regard to using NATO membership (for Ukraine) as a bargaining card (or something to trade for something else): at least one NATO member-country has shared the idea with authorities outside its own government. In August 2023, the Director of the Private Office of the NATO Secretary General said that "I think that one solution could be that Ukraine gives up [land or] territory, and gets a NATO membership" [as part of that deal or] in return".