The amendment infuriated Graham, a South Carolina Republican with close ties to another presidential hopeful, Sen. John McCain, R-Ariz. Pacing the Senate floor and waving Obama's amendment, Graham loudly accused Obama of undermining a delicate agreement whose advocates have shown political courage. Issues that require bipartisanship often fail, Graham said, "because some people, when it comes to the tough decisions, back away." Obama's amendment, he said, would destroy the bill's prospects and bring special woe to Republicans—such as himself—who have endured conservatives' searing criticism for backing it. It would undercut "everybody over here who's walked the plank and told our...