Opposing war in Iraq is not, has never been, and will never be Church doctrine.
Abortion is an unqualified evil. That is Church doctrine.
But, if a particular bishop thinks it is, or thinks that politicians supporting capital punishment (which has been pretty well condemned by JP II) should be refused the Eucharist, he will point to this "policy" as his pretext.
I don't think Gregory is trying to give the election to Kerry; I think he's trying to avoid giving the election to Kerry.
This kind of thing, if not handled deftly, has a way of backfiring.