LONDON - Whatever plan Russian President Vladimir Putin may have had when he first ordered his troops into Ukraine, he surely did not expect to be facing a second week of fighting with the Ukrainian government still in power and Russian troops still struggling for the possession of every village.

But military campaigns have a knack of producing unexpected outcomes, and Mr Putin is now facing the classic dilemma other world leaders before him encountered; that, while it is easy to start a war, it is much more difficult to finish it.