Some commentators say that the push to bring Georgia into NATO provoked Putin into attacking, at least as a contributing factor.  It primed him to take an aggressive posture with respect to emerging democracies that once comprised the Soviet Empire.  I tend to agree with this premise, at least insofar as it provided a clear cost comparison for Russian intervention.  If Russia were to seek to re-assert its control over Georgia, it would be cheaper and less risky to do so before the latter joined the western alliance.  Furthermore, expanding NATO into the former USSR is most certainly on its face threatening to the re-emerging great power (and potential regional hegemon).  So, the push to bring Georgia into NATO provides both a reason and a time-frame for Russian aggression.

Still, we should not stop there in assessing the prospects of Georgian inclusion in NATO.  Many people look at the current situation and say, "good thing they're not in NATO, otherwise Article 5 would require that we join a shooting war against Russia."  However, this does not address the primary question, would Russia have attacked a NATO member country, knowing full well the commitment of Article 5.  There are two possible answers: yes and no, and determination of which would determine the fate not of Georgia alone, but of NATO itself.  In other words, if NATO is a threat to Russia, Putin might test the strength of the institution by triggering an Article 5 response and seeing if the weapon was loaded.  Then, the future of NATO would depend on U.S. willingness to engage in a fire-fight with Russia.  If we weren't willing to do so, then Article 5 would no longer constitute a credible commitment, at least when facing a real military threat (as opposed to, say, the Taliban, which is a threat, just not a military one). 

Now, I can't say for certain what would happen, and much would depend on the inhabitant of the White House, but I can't see the U.S. being in such a great position to wage another war at the moment.  And Russia attacking a NATO member would require Putin to have a strong gambling streak, which I wouldn't put past him.  But to be clear about what's on the line in allowing Georgia into NATO: it's the institution itself.  In simple rational terms, we would have to decide if the benefits of including Georgia (moral, strategic, or otherwise) would justify the risk to the alliance's survival.