It's not just that Keegan lies above, but that it is such a preposterous lie.
To wit: if Serbia wanted to be beligerant, say, to rely upon Russia to back Austria down, then it would have simply rejected Austria's ultimatum.
There was no need for Serbia to capitulate on 3 of Austria's four main demands, after all, if Serbia intended to be defiant.
So Keegan's lie doesn't even pass the most rudimentary of smell tests. It stinks.
What Serbia did was to capitulate on all of Austria's demands, save to *suggest* that the Hague arbitrate Austria's demand of having Austrians enter Serbia to be involved in all phases of the apprehension of anti-Austrians and the shutting down of all anti-Austrian publications.
This capitulation was so complete, and the diplomacy involved so well done, that Germany's Kaiser William II himself read it and said that there was now "no excuse for war."
That's directly from the source. Germany was Austria's key ally. Kaiser William II was the absolute, uncontested ruler of Germany, and *his* authoritative response to the Serbian capitulation was that now there would be no war.
Austria invaded Serbia anyway. There were no further "negotiations." Not even an attempt.
Well, I got an eminent British war historian, author of many acclaimed, highly researched books, on my side. What have you got?
Keegan, in the quote I gave you, explains with precision how and to what extent, the Serbian stance evolved following the signals from the Russian Tsar.
You wonder why Serbia did not reject the ultimatum in toto. Obviously, it needed to appear reasonable enough to provide cover for the Russians' saber rattling.