Even before contact was initiated, there were casaulties. Heinlein was first, he was supervising the loading of anti-matter missiles into the belly of his drop-ship when a chance state change of a neutrino neutralised the containment field. The resulting explosion took out half of Ohio and created a sixth Great Lake.
Meanwhile in Scotland, Stross had been attempting to negotiate some kind of deal between the two sides. Simultaneously running eighty-six Charlie-Bots, each a limited AI pumped up with Tillingast Algorithms and protected by Doctorow Shields, and sustained by a steady feed of Decembrists and Irn Bru, he'd a least brought the sides together. The to and fro of offer and counter offer had been intense. At one point the drain on the national grid was such that it blacked out all the chip shops in Leith. However a previously unknown Mac virus performing a global find and replace of the word "Singularity" with "Flying Spaghetti Monster" brought the Creationists out in force and he'd been no match for the assembled might of 9,000 JesusMemes: he'd been burted.
At midnight, on the 30th of November, a huge flotilla of attack ships uncloaked and appeared, hovering over Boston. In London, Canary Wharf unfolded from a building to a kilometre tall robot warrior, the windows of plassteel gleaming in the early morning light. Nine milliseconds later, battle was joined over the southern tip of Greenland.