Three months after a rift between GOP party leaders and grass-roots conservatives led to the special election loss of a historically Republican-held seat in upstate New York, another campaign melodrama is taking shape in the same district. Doug Hoffman, last November’s Conservative Party nominee in New York’s 23rd District who is vying again for the seat, is refusing to rule out running as a third-party candidate this year if he fails to win the Republican primary. And his leading backer, Conservative Party Chairman Mike Long, told POLITICO that he refuses to endorse any candidate other than Hoffman — raising the...