Just four days after MH17 was brought down over the Ukraine, Russia scholar Matthew Sussex wrote  a scathing assessment of Moscow's early reaction to the incident for The Interpreter. But he closed his piece by arguing that it could have been much worse: 

...Putin could have expressed horror at the loss of MH17 and promised to persuade the separatists to stop fighting immediately, regardless of any 'provocations'. He could then have called a Security Council meeting to guide its focus towards accessing the crash site, rather than who was to blame. Finally (and this is the insidious part) he could have declared Eastern Ukraine a dangerous warzone and unilaterally nominated Russia as the regional power with the capacity to secure it. That could have been the pretext to roll 12,000 troops across the border, ostensibly to create a cordon sanitaire to MH17's resting place.

Now NATO is warning that Russia may be contemplating that very strategy:

Russia has amassed around 20,000 combat-ready troops on Ukraine's eastern border and could use the pretext of a humanitarian or peace-keeping mission to invade, NATO said on Wednesday. Stating the conflict in Ukraine was fueled by Russia, NATO said in a statement that the troop build-up had further escalated "a dangerous situation".

"We're not going to guess what's on Russia's mind, but we can see what Russia is doing on the ground – and that is of great concern. Russia has amassed around 20,000 combat-ready troops on Ukraine’s eastern border," NATO spokeswoman Oana Lungescu said in an emailed statement. NATO was concerned that Moscow could use "the pretext of a humanitarian or peace-keeping mission as an excuse to send troops into Eastern Ukraine", she said.

A fortnight ago I wrote an op-ed for the Financial Review arguing that, for Australia, the MH17 shootdown was a consular crisis, not a test of foreign policy. My purpose was to warn that Australia ought to be wary of involving itself too closely in the power politics of this crisis. Australia has few interests at stake in the region, and Russia is not a serious threat to Australia's interests.

Further catalysts for closer Australian involvement are now emerging: overnight there was an announcement that Russia is imposing sanctions that will target Australian agribusiness. And now, according to NATO, there is a heightened threat of Russian invasion, which apart from being a crisis for Europe, would be particularly serious for Canberra if Australians working at the crash site were caught up in it.