Being a friends means having their back when someone bigger attacks them. When times are good everyone wants to be your friend but a true will be there when you are down.
Picking Russia as a friend because they are stronger makes you weaker.
So you're proposing war with Russia over the Ukraine then? Because that's the alternative here.
Fortunately it is possible to be friends with someone without fighting someone else. That's how 99% of friendships work 99% of the time. The US and UK are allies even though the US didn't fight Argentina in the Falklands and the UK never really engaged in Vietnam.
> If the Ukraine was part of NATO and Russia invades that triggers an automatic response.
No, it triggers treaty obligations. Adherence to those is not automatic. Of course, if NATO admitted Ukraine now, given that there is an ongoing war in which Russia is openly occupying part of Ukraine and attacking other parts, it would be very close to a declaration of war by the existing NATO powers against Russia.
> The UK didn't request assistance in the Falklands
NATO’s collective defense obligations only applies to attacks on member-state territory in Europe or North America. [0]
The Falkland Islands are very much
not in either of those continents.
> Russia claims that they are not participating in any hostilities in Ukraine
Article 5 is triggered by attacks, not whether the attacker claims they are attacking, and both Ukraine and NATO already officially recognize the fact of Russia’s military intervention in Eastern Ukraine as well as the harder-to-obfuscate fact of Russia’s occupation of Crimea.
None of the examples you cited are relevant to NATO. Vietnam and the Falklands are outside the statue of Article 5, unambiguously.
Ukraine will never be part of NATO. For it to be would require change to the NATO approval process that bars states with territorial disputes from entering, and any attempt to change this would be seen by Russia (correctly) as a declaration of war and they would successfully invade the rest of Ukraine.
Beyond that, it's not even certain NATO would risk nuclear warfare to save Ukraine. Because that's what it would take. Russia has the firepower to make sure the status quo will not change, no matter what.
There's no reason for Russia to take over the entire Ukraine. Ukraine is a failed state, poorest country in Europe, it is drowning in problems. Just look at the stats from ukrstat.gov.ua
It was a dream of US and EU that Russia would take over the entire Ukraine, so that Russia would have to feed the hostile population and at the same time suffer more sanctions. But thankfully we didn't pick the bait. Now Ukraine is like a "suitcase without a handle" for EU and US: too inconvenient to continue carrying and seems too valuable to simply throw it away. They have to feed it to prevent a complete collapse, but they don't have any more gains from having Ukraine under control.
Moldova is the poorest country in Europe. Ukraine is 2nd and Serbia is 3rd. Out of some wacky coincidence these are also the European countries that had very strong alignment with Russia.
Out of some wacky coincidence all the countries where US staged color revolutions (Ukraine, Georgia, Kyrgyzstan, Tunis, etc, etc) are doing much worse in all areas of life than before.
Picking Russia as a friend because they are stronger makes you weaker.