Mr Cameron has urged the international community to stand up to what he has described as Russia's "bullying" of a smaller country. "Russia has used massive and disproportionate force against an independent and sovereign democracy," he said.
"This is completely unacceptable under international law and we and our allies must not beat around the bush in condemning Russia very clearly. It looks increasingly as if Russia intends to topple the elected government of Georgia and to try and cripple that country."
But what, you may ask, can an opposition leader actually do? Well, there is something: he can send diplomatic signals.
In the Council of Europe’s parliamentary assembly, Conservative members sit not with moderate right-wing parties such as the German CDU/CSU or the French UMP, but alongside more hardline groups such as the Danish People’s Party, the Italian National Alliance and the Polish Law and Justice party.
Oh yes, and the United Russia party of Vladimir Putin and Dmitry Medvedev (hat tip to Denis MacShane).
The so-called European Democrat Group is chaired by a United Russia member, with Tories sitting as honorary president (Baroness Knight, original author of Section 28), vice-chair (David Wilshire MP, another key Section 28 sponsor), political officer (Robert Walter MP) and co-treasurer (Christopher Chope MP, who as a minister championed the poll tax even after Major replaced Thatcher).
If the Tories so vehemently oppose this Russian aggression, why do they persist in sitting with the party that sent the tanks into Georgia? Why doesn’t Cameron pull his people out of there?
(Update: Labour Matters takes up the cudgel.)