War gets modern politicians that way. It inspired Maggie Thatcher in the Falklands and it enthused George Bush in the Gulf. But politicians should beware of the pleasures of the heady moral fervour that goes with war.
Mr Blair has made much of the appalling plight of the refugees from Kosovo. Until a sudden acceleration of activity in the last week, he and his Government had done rather less to give succour to the needy by providing residence in Britain. It is all very well for the British Prime Minister's staff to say, as they did yesterday, that Britain has responded to such specific requests that have been made and that it is willing to take many more.
But compassion cannot be limited to those who have put their request in writing and sent it through the proper channels. Nor was Mr Blair willing to put a number on his offer. Compared to the tens of thousands of refugees taken by Germany, even a couple of thousand more - which seems all that is likely in practice - is pretty small, far smaller than the outpouring of public generosity would warrant. If this is a war of moral imperative, then the Allies must seem ready to sacrifice their own convenience and some of their wealth on behalf of the victims, and not just some of their surplus missiles.
The same could be said for the war effort as a whole. Mr Blair has talked much - he is at it again on his visit to the Balkans - of the new principles of moral intervention and peacekeeping. He has been much less forthcoming about the cost of this in the lives of soldiers, in the money to be spent on our defence forces and in the sums we shall have to commit to reconstruction after these interventions.
The Prime Minister praised to the full yesterday the courage and the commitment of British pilots and the forces in Macedonia and Albania. And he was right to do so. But he knows, as the British public knows, that the commitment required to bomb from the air is a very different commitment from that of putting troops on the ground. The ground forces capable of invading Kosovo are beginning to be assembled. The British contingent will be up to 6,500 by the middle of this month. But are they to be used for offensive action, or are they to sit on their hands until there is a settlement?
The British Prime Minister has a way with fine words. But too often in this war - over the refugees, the cost and the ultimate likelihood of a ground war - he is using them not to clarify intentions but to skate over the differences between reality and emotion.