First, the case of Crimea was also a "special case". The Russian were legally present there and, in the Russian rationale, all the "Polite Armed Men in Green" did was to protect the local population to make it possible for the latter to freely express its will. Only after that will was expressed did Russia agree to formally re-incorporate Crimea into Russia. So from the legal Russian point of view, none of the Russian actions in Crimea included any form of violation of Ukrainian sovereignty. I know, most western analyst will not agree, but that is the official Russian stance. And official stances are important because they form the basis for a legal argument.
Second, the aid which Russia has been sending to Novorussia has been exclusively covert. Covert operations, no matter their magnitude, do not form the basis for a legal position. The official position of Moscow has been that not only was there absolutely no military aid to Novorussia, but even when Ukie artillery shells landed inside Russia did the Kremlin authorize any retaliation, again in (official) deference to the Ukrainian national sovereignty.
This time, however, there is no doubt at all that the Russians did deliberately and officially chose to ignore Kiev and move in. Now, in fact, in reality, this is clearly the logically, politically and morally right thing to do. But in legal terms, this clearly a violation of Ukrainian sovereignty. From a legal point of view, the Ukies had the right to keep the Russian convoy at the border for another 10'000 years if they wanted and Russia had no legal right to simply move in. What apparently happened this morning is that the Ukie officials did not even bother showing up, so the Kremlin just said "forget it!" and ordered the trucks in.
Not only did the Russians move in, but they did that without the ICRC whose personnel refused to go because of the lack of security guarantees from Kiev. The Russian response to that lack of security guarantees was a) to order this unarmed convoy in and b) to clearly state in the official statement:
We are warning against any attempts to thwart this purely humanitarian mission which took a long time to prepare in conditions of complete transparency and cooperation with the Ukrainian side and the ICRC. Those who are ready to continue sacrificing human lives to their own ambitions and geopolitical designs and who are rudely trampling on the norms and principles of international humanitarian law will assume complete responsibility for the possible consequences of provocations against the humanitarian relief convoy.Again, from a logical, political or moral point of view, this is rather self-obvious, but from a legal point of view this is a threat to use force ("complete responsibility for the possible consequences") inside the putatively sovereign territory of the Ukraine.
The US and their main agent in Kiev, Nalivaichenko, immediately and correctly understood the threat: not only did this convoy bring much needed humanitarian aid to Lugansk, it also provided a fantastic political and legal "cover" for future Russian actions inside Novorussia. And by "actions" I don't necessarily mean military actions, although that is now clearly and officially possible. I also mean legal actions such as recognizing Novorussia. From their point of view, Obama, Poroshenko, Nalivaichenko are absolutely correct to be enraged, because I bet you that the timing, context and manner in which Russia moved into Novorussia will not result in further sanctions or political consequences. Russia has now officially declared the Ukie national sovereignty as "over" and the EU will probably not do anything meaningful about it.
That, by itself, is a nightmare for Uncle Sam.
Furthermore, I expect the Russian to act with a great deal of restraint. It would be stupid for them to say "okay, now that we violated the territorial integrity of the Ukraine and ignored its sovereignty we might as well bomb the junta forces and move our troops in". I am quite confident that they will not do that. Yet. For the Russian side, the best thing to do now is to wait. First, the convoy will really help. Second, it will become a headache for the Ukies (bombing this convey would not look very good). Third, this convoy will buy enough time for the situation to become far clearer. What am I referring to here?
The Ukie plan has been to present some major "victory" for the Sunday the 24, when they plan a victory parade in Kiev to celebrate independence day (yup, the US-controlled and Nazi-administered "Banderastan" will celebrate its "independence"... this is both sad and hilarious). Instead, what they have a long streak of *very* nasty defeats during the past 5-6 days or so. By all accounts, the Ukies are getting butchered and, for the first time, even pushed back (if only on a tactical level). That convoy in Luganks will add a stinging symbolical "f**k you!" to the junta in Kiev. It will also exacerbate the tensions between the ruling clique in power, the Right Sector and Dmitri Iarosh and the growing protest movement in western Ukraine.
Bottom line: this is a risky move no doubt, probably brought about by the realization that with water running out in Luganks Putin had to act. Still it is also an absolutely brilliant move which will create a massive headache for the US and its Nazi puppets in Kiev.
PS: I heard yesterday evening that Holland has officially announced that it will not release the full info of the flight data and voice recorders of MH17. Thus Holland has now become an official accomplice to the cover-up of this US false-flag operation and to the murder of the passengers of MH17. This is absolutely outrageous and disgusting I and sure hope that the Malaysian government will not allow this. As for Kiev, it is also sitting on the recording of the communications between the Kiev ATC and MH17. Finally, the USA has it all through its own signals intelligence capabilities. So they all know and they are all covering up. Under the circumstances, can anybody still seriously doubt "who done it"?