first they like to do it in August, the latest example being Georgia
secondly, as always it is a problem of logistics and organizing something overlooked by journalists addicted to twitter and realtime war on tv thinking that everything 'just happens'
there is however also good news and that is that the military news for the Russians is not only good but is growing worse every week and the risks are increasing while the benefits of an invasion are diminishing
this doesn't mean that he isn't trying and that provocations and proposals for humanitarian interventions or corridors won't continue - but I have never seen a leadership so Ghandi-like as in Ukraine refusing to fall in the laid-out traps (even if most of the false flag operations were so amateurish you begin to doubt the reputation of the effective KGB)
"Well, it’s probably cold comfort, particularly to those facing them, but I don’t think all those Russian troops massed along the Ukrainian border are as battle-ready as their chain of command would like us to think. The overwhelming majority are 12-month conscripts, and so probably of less utility than one might think. Russian law requires that Russian conscripts may not be sent to a combat zone until they have had at least six months of training, but six months’ training produces a very basic soldier, not one capable of a whole lot more. The draft cycles run in fall and spring which probably leaves Russia with pretty narrow windows for launching a military campaign: the spring 2014 class isn’t fully trained up yet, while the Fall 2013 class is already antsy short-timers. In terms of trained soldier availability though, I might invade in late August to early September to best take advantage of Russia’s available conscript manpower. That also just happens to be the same time of year when Russian runs its annual set-piece military exercises. Thanks to Russia’s archaic military manpower system, the upcoming six weeks are the most potentially dangerous for a potential Russian invasion of Ukraine.