The Catholic bishops of the US are on record as having grave doubts about a war with Iraq being "just": see this press release.

I know the Mennonites, Quakers, and Brethren do, but these are traditionally pacifist religions.

I wonder what would happen if the US bishops made a statement to the effect that since a war with Iraq was unjust, participating in or supporting it in any way would be gravely sinful?