It won't. Baltic countries are safe - sure Russia sometimes tries to harm them, but it never uses military tools to do that because Kremlin knows what it would mean.
And you're right, at least in the short term. Adding a potentially very unstable countries to NATO would be a mistake.
Russians are returning to the imperialist policies of the past and the West is right to oppose them. If you want to face reality, face this: no matter what the West does in the area of fromer USSR, Russians will inevitably see it as a provocation and an aggressive move. Again, nothing we can do about it - if they want to see the West as the enemy, what
could we do? When my country offered to host a part of the US missile defense system, the Russians reacted almost hysterically despite knowing the system cannot hurt them or their interests. Hours later, a "sudden technical problem" reduced the oil flow to the Czech Rep. by 40%, surely it was just a "coincidence". See, 20 years after the collapse of the Eastern Bloc, they believe we should ask them for permission when we want to have our own foreign policy. Imagine what they expect from countries which actually border with Russia.
Russian foreign policy is a mixture of rational (cynical) and irrational elements. They're rationally (cynically) trying to expand their influence and reduce the Western ability to interfere with Russian plans - this is why they're so loud about the missile defense which they know is harmless, this is why they support Venezuela, Iran and others. These countries are a distraction, something Russia can use as a leverage against the West:
"We help you with Iran, but you give us free hand in Ukraine". The only problem in that is that this policy is more suited for the 19th and 20th centuries, not this one and the West often refuses to play by the same rules.
The irrational aspect is the traditional Russian paranoia and their fear of encirclement by encroaching foreign powers. Expansionism has been a part of Russian foreign policy for the past 500 years, it carries a lot of inertia. After the period of chaos, the Russians believe now's the time to use Russia's wealth to expand the empire again. This irrationality is also making it next to impossible to maintain good relations with Russia - it will inevitably see any Western influence in areas like Eastern Europe, Caucasus or Central Asia as an aggressive move, even though the West doesn't mean it that way.
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I say we have to live with it - appeasement of Russia won't help, they'd just see it as our weakness and become even more aggressive. Russia needs to be contained until it stops acting like an international bully.
(and please, no "others are the same!" crappy pseudo-arguments, they're irrelevant to this discussion).
Nobody says the West shouldn't talk with Russia, but talking =/= giving them what they want. If Russians had it their way, NATO would have to dissolve itself, all former commie countries would have to bow to Moscow and the US... well the best thing would be if they left Europe, dismantled all their nukes and offered the presidency to a Russian
Jokes aside, being nice to Russians won't bring you the desired results. They understand power, so let's use it - set up clear limits of what they can and can't do. First things first - bullying independent countries in their neigbourhood is not acceptable.