a bit more on this: this is, obviously, a statement about dialectics. what the ICL is saying in dialectical terms is this: there exist, as described in the General Political Line of the PCP (a seminal document for MLMism), contradictions between imperialist powers- and some, of course, are principal over others. So two imperialist powers (e.g. the UK and the US) may unite against another (Russia) if their struggles against it trump those against one another. But, say the ICL, they will always return to vicious struggle with one another once these more prominent contradictions are resolved or at least ameliorated and the lesser ones become principal. This would seem to mean that inter-imperialist contradictions are always essentially antagonistic- given the infamous drive of finance capital to own everything, and to take it away from every other pole of finance capital, this seems conceivable, but again I do not know for sure that it is certain.