The other is the Prime Minister's surprising and apparently reckless absolutism in his conduct of the war. From the outset he has confounded his image as a cautious politician by ruling out any "exit strategy" - except total victory. Even when President Clinton and Chancellor Schroder were at their most flaky last week, he blithely insisted there could be no compromise, and that all options, including the use of land forces, remained open.
Last week the mood of the commentators swung furthest against Tony Blair. He looked isolated and - however morally justified - naive. Public opinion and political leaders in other Nato countries simply did not appear to have the stomach for a costly ground war.
Then two important things happened. One was the first evidence that Serb military morale might be cracking. The other was the first sign of a shift in the American position in favour of ground troops. Coming just after White House leaks of Bill Clinton's rage against his friend Mr Blair for suggesting there was a split between them on this issue, this can only mean one thing. Which is that Mr Blair has, in effect, won the argument.
The President is annoyed because he has been portrayed back home as trailing in the wake of the "hawk of Nato". But he has agreed to send more troops to the Balkans because otherwise Nato - and the United States - risk being humiliated by a nasty, brutish and now, possibly, short-term dictator.
It has taken a while, but Mr Blair has what he wanted, and what should have happened long ago: a build-up of 50,000 Nato troops on the borders of Kosovo. For the sake of Nato unity, we cannot speak of invasion or even of fighting the Yugoslav army. But we can say, as Robin Cook did yesterday: "It would be more than just a peace-keeping force. It's... a substantial military force capable of providing real security and reassurance to the people of Kosovo."
It may be that in due course Mr Blair and Mr Cook will talk of Nato forces "escorting" Kosovar Albanians to their homes in a "semi-permissive environment". No matter: if it achieves the ends to which Nato is unanimously committed, it does not matter what anyone calls it. It would of course be a tremendous vindication for Mr Blair. More importantly, it would be a victory for human rights and international justice.