To truly be pro-life "means far more than opposing abortion. It also means doing everything in our power to keep people alive, so they might respond to the grace of Jesus Christ. Sometimes that means working with people you disagree with. With AIDS killing 8,000 people a day, saving lives is more important to us than political alignment." - part of a statement released by Saddleback church in reponse to criticism that Rick Warren received when he decided to have Senator Barak Obama speak at the Saddleback AIDS Summit yesterday.
There is a great post on Out of Ur, the Leadership Journal blog about working with people you disagree with.