WASHINGTON (AP) -- Architects of a revived immigration compromise are directing an intense behind-the-scenes bargaining effort to round up enough votes among wavering Republicans to keep it alive. Senate leaders' announcement Thursday that they would allow the bill a second chance came after getting assurances from key negotiators that they could produce enough support to steer the measure through a procedural minefield, including attempts by conservatives to block it. The fragile compromise would grant millions of illegal immigrants lawful status while tightening border security and creating new measures for weeding out illegal workers at job sites. Championed by President Bush,...