Pro-Obama super PAC Priorities USA positions itself to support Hillary Clinton The emergence of Priorities as a pro-Clinton ally would introduce a heavyweight player into the rapidly intensifying effort by super PACs to shape the 2016 landscape. The people familiar with the plans said Priorities is developing a different mission than Ready for Hillary, a group started this year by ardent Clinton supporters and now backed by longtime Clinton associates. While Ready for Hillary is focused on grass-roots organizing, Priorities is planning to become what one of the Democrats called "the big money vehicle" that would produce and air expensive television advertisements. The people spoke on the condition of anonymity because the plans for Priorities have not been finalized. Priorities strategist Paul Begala, a former Clinton White House adviser, declined to comment on behalf of the super PAC. One of the Democrats said Priorities is not planning to become active in the race until Clinton "gives a definite nod that she's going to run." Already, however, conservative super PACs, such as the Stop Hillary PAC, have jumped into the fray with attacks on Clinton - activities that could prompt her allies to launch a media response before she decides whether to get in the race. Priorities, started by two former Obama White House aides, was widely regarded as one of the most effective independent groups in the 2012 presidential race. After a sluggish fundraising start, the super PAC ended up raising nearly $80 million - money it poured into a relentless barrage of television commercials that portrayed Romney as an elitist corporate raider during the 2012 presidential election campaign. Unlike federal candidates, super PACs can accept unlimited contributions, as long as they do not coordinate their strategy directly with candidates or political parties. Although Priorities spent far less than the pro-Romney super PAC, Restore Our Future, the group's early and consistent focus on Romney's record at Bain Capital put a negative cast on his business experience that proved hard for the GOP nominee to shake. "They got off to a slow start, but they had a really strong finish, and ultimately they received a lot of credit for the negative messaging that was most effective against Romney," said Phil Singer, a Democratic strategist who ran the war room for Clinton's 2008 White House bid. Priorities has been able to establish credibility. Refashioning itself as a pro-Clinton super PAC would be a natural fit for Priorities, which already has strong ties to both Bill and Hillary Clinton. Sean Sweeney, who was the top aide to then-White House chief of staff Rahm Emanuel, helped launch Priorities with former White House deputy press secretary Bill Burton and continues to steer it. Sweeney worked as a legislative assistant for then-Sen. Hillary Clinton, and people in Clinton's orbit described Sweeney as a trusted loyalist.