Interesting essay arguing why any negotiated settlement of the war must necessarily include NATO membership for Ukraine.
What the war has shown is that anything short of a full-NATO membership is in security terms, worthless. Ukraine actually had different types of security guarantee given to it a number of times since the dissolution of the USSR. According to the Budapest Memorandum of 1993, for instance, Ukraine agreed to give up Soviet nuclear weapons in its border. In exchange for this, Ukraine had its full territorial integrity, including Crimea, recognized by the USA, Russia and the UK. Of course this did nothing to stop both the Russian invasion of Crimea and Donbas in 2014 and what has come later.
If Ukraine is going to have enduring, long term security after the war, it will only be through full membership of NATO and the application of NATO’s Article 5. This fundamental difference between Ukraine and the Baltic states, for instance is what has kept Putin, for instance, from ever convincingly threatening other former members of the USSR such as Latvia, Lithuania and Estonia. Its also why immediately after February 24, Finland and Sweden did their historic pivots and decided to become NATO members.