Not the reason though. Kosovo was not a part of NATO either. It's just that Russia is not Serbia.

Vietnam wasn't part of NATO either, I guess if we're just pointing things out.

Even if they were, what's easier, to honour such an agreement with an expensive (materially and in terms of human lives) and dangerous (would cause the conflict so spread) deployment or to say "Sorry, you're going to have to tough it out yourself.".

The USA and UK already abandoned the Afghani people, feels like the once mighty US military really doesn't want to be in a shooting war against Russia. As someone living in Europe, I would also be wary of how it would escalate if NATO got involved.

> Even if they were

You would have to weigh how things would escalate if NATO got involved, vs how things would escalate if Russia found out NATO isn't actually a thing any country intends to honor.

The US will defend NATO. They will nuke Russia's forces if they try to enter Poland. There is no doubt in my mind that is a red line.

They will definitely defend Poland. They won't nuke, not even tactically.

There should always be plenty of doubt in your mind if you're saying that the US will use nukes in any situation short of someone else using them first.

The difference is that US is actually putting their troops and equipment in Poland though. I also think that attack on Poland would trigger full out response by US.

Poland is a NATO state. An attack on Poland would trigger World War 3 because the whole alliance is set up to jump in.

I really doubt it. Most likely NATO would destroy any all Russian forces that enter Polish soil but not push further out past the border and escalate. No need to start WW3.

The US has explicitly refused to adopt a no first use posture.

Ditto Russia, UK, France, the other nuclear powers involved.

That being said, it’s a Rubicon all, will be reluctant to cross.

The US is the only country that used nukes.

This isn't even a remotely similar situation. The biggest difference is that last time around, we were the only people with nukes and (agree with the decision, or not) it was a war ending use of nukes, with zero chance of starting a world war, nuclear or otherwise.

Among other things, those experimental first bombs were a totally different class of weapons from today's nuclear arsenal. There were conventional bombings in WWII that killed more people than the nuclear bombings.

The UK is the only other nuclear power to have detonated nukes on the territory of another country.

Completely irrelevant.

No, in fact very relevant. Not in the way the OP probably meant it though.

The US will defend NATO unless it feels it isn't the best thing to do at the time.

Putin would have never invaded a NATO country.

Feels like until 5AM local this morning we all thought he'd never do a full invasion of Ukraine either...

But in general I'd agree with you. On the other hand, who and literally what army would stop them?

> Who and literally what army would stop them?

Among several others, the United States military. Which, contrary to claims made elsewhere in this thread, is a pretty formidable defensive force. In fact, it even has aircraft carriers that can move under their own power.

Yeah, Biden vowed to defend ‘Every Inch’ of NATO Territory. Any Russian soldier unfortunate to step onto NATO soil is going to get obliterated by the US military.

NATO is much more powerful than Russia, furthermore NATO has nuclear capabilities, you just don't invade a country that has nukes.

There is not a single chance that Russia would have touch a NATO country, it's a war they could not win.