The Church teaches that physical and moral torture is a sin against the dignity of the human person. From the Catholic Catechism:
2297 Kidnapping and hostage taking bring on a reign of terror; by means of threats they subject their victims to intolerable pressures. They are morally wrong. Terrorism threatens, wounds, and kills indiscriminately; it is gravely against justice and charity. Torture which uses physical or moral violence to extract confessions, punish the guilty, frighten opponents, or satisfy hatred is contrary to respect for the person and for human dignity. Except when performed for strictly therapeutic medical reasons, directly intended amputations, mutilations, and sterilizations performed on innocent persons are against the moral law.
As Catholics and Christians, we likely all agree with the above teaching. However, what the definitive definition of torture actually is, is still undefined, even by the Church. As a Catholic and a military wife, I'm a bit conflicted when the definition of torture includes water boarding. Many folks I respect and admire would argue that water boarding does indeed constitute torture. Others I equally respect and admire wholeheartedly disagree. For myself, the words "uses physical VIOLENCE" stick out and I am inclined to say water boarding does not inflict actual violence. I will say, I sure am glad I am not personally tasked with making any sort of determination on what constitutes torture. What do you think? Check out the post and read some of the comments here.