Bush's Veto

During his remarks about vetoing the embryonic stem cell bill today, President George W. Bush talked about the importance of saving all human life. He stated:

America is also a nation founded on the principle that all human life is sacred.

... Destroying human life in the hopes of saving human life is not ethical.

Bush clearly believes that one should not destroy a few lives in order to save many because all life is sacred. With that belief how can he justify the Iraq war? He said it was to save many lives from an attack by terrorists with weapons of mass destruction. But he surely knew that some lives would be lost in that mission. Why does being pro-life seem to mean that we only care about life up until the point someone is born?