Cardinal Joseph Ratzinger (Benedict XVI):
"Not all moral issues have the same moral weight as abortion and euthanasia. For example, if a Catholic were to be at odds with the Holy Father on the application of capital punishment or on the decision to wage war, he would not for that reason be considered unworthy to present himself to receive Holy Communion. While the Church exhorts civil authorities to seek peace, not war, and to exercise discretion and mercy in imposing punishment on criminals, it may still be permissible to take up arms to repel an aggressor or to have recourse to capital punishment. There may be a legitimate diversity of opinion even among Catholics about waging war and applying the death penalty, but not however with regard to abortion and euthanasia."
http://www.priestsforlife.org/magisterium/bishops/04-07ratzingerommunion.htm
I actually know the quote.
And to be honest (as I suspect you know) it isn’t that way in the trenches. I know of people who got in a lot of hot water with their priest over the Iraq war because of statements made by the Pope.
Also, those topics aren’t the same as what is being talked about here. A better example (if not remarriage and receiving communion) would be if a Pope came out and said that abortion is ok in situations where there was not a clear and present danger to the life of the mother. The Catholic church as pretty much always been against abortion (and remarriage after divorce). It has not always been against capital punishment.