US President Barack Obama will lay out a jobs package worth more than $300 billon on Thursday, staking his re-election hopes on a call for urgent bipartisan action to revive the faltering economy. With his poll numbers sliding to new lows amid voter frustration with 9.1 percent unemployment, Obama will make tax cuts for middle-class households and businesses the centerpiece of the plan and will press for new spending to repair roads, bridges and other deteriorating infrastructure.