The concept of mercy spans testaments and faiths, and any system of justice requires the embrace of mercy for leavening and legitimacy. In this case, justice has been served by Lindh's time in prison. Now Bush is uniquely positioned to grant mercy, for while many will long argue over the effectiveness of his war on terror, none question his commitment to it. By giving Lindh a commutation, Bush could prove that his war is, as he often and properly asserts, not against Islam but against those who seek to harm America. Lindh never sought to harm his country; he has...