Chicago Mayor Rahm Emanuel, President Obama’s former chief of staff, has stepped down as a cochairman of Obama’s reelection campaign to focus on raising large donations for a super PAC supporting Obama, according to news reports.

Emanuel is a highly regarded fund-raiser and was one of the first members of Obama’s team to suggest that Democrats should establish a strong super PAC to aid the president, according to a recent e-book by Politico reporter Glenn Thrush.

In February, Obama announced he would encourage supporters to donate to Priorities USA Action, a super PAC formed by former aides.

So far, Priorities USA Action has failed to compete with its conservative counterparts, raising $25.5 million. Restore Our Future, a pro-Romney super PAC, has collected almost $90 million. Another conservative super PAC, American Crossroads, has raised $47.3 million.