ubiq: “Only someone extremely delusional can argue Ukraine poses a threat to Russia. THAT is the discussion.”
A Ukraine that is part of NATO can be considered threatening to Russia. Let’s take the following example to illuminate this point. Crimea was part of Russia for centuries until the Ukrainian dictator of the USSR simply transferred Crimea from Russia to Ukraine unilaterally in 1954. After the breakup of the Soviet Union in 1991, Ukraine simply kept Crimea. If Russia were to later contest Ukrainian sovereignty over Ukraine (as it did) on the basis that the 1954 transfer was illegitimate or that Crimean residents are vast majority ethnic Russians who prefer that their province be part of Russia, such a dispute between Russia and Ukraine is a far greater national security threat to Russia if Ukraine will have NATO, including a nuclear US, UK and France, militarily defend Ukraine against Russia.