guys-

when the old soviet union tried to place nuclear weapons in the us's backyard in cuba, the us objected. likewise, it appears that nato membership confers the ability to place wmd in the backyard of modern russia. the fact that it is the business of those countries does not change that a coddled autocrat has made clear that this is a red line. as i understand it, the us ignored many years of warning from russia that continuing to pursue the old cold war thinking could provoke a response from russia. now that appears to be what has happened.

the reality is, or seems to be, that the choices were to leave the eastern european situation alone in return for an uneasy situation but a greater likelihood of status quo, or pursue the old nato alliance expansion and increase a risk of russian response. it seems the us just kept hammering away at the nato membership thing and now we have the russian response. that is the theory anyway.

If Sweden, Finland, or Ukraine are each sovereign countries and feel like joining NATO that’s their business.

I've got to admit I don't know.... But one question occurs to me.
How many countries has NATO invaded? How about invaded in defense?

Nuclear missiles are of course a larger threat. But how will invading Ukraine protect Russia from them? Idiots elsewhere in the world are just as capable of launching at Russia regardless of whether Ukraine is there or not. The most likely reason for Ukraine to cause a nuclear launch on Russia is if Russia attacks Ukraine or a NATO country -- which Russia has done with Ukraine.