Scott Walker’s Exit Shows Limits of ‘Super PAC’ Money Model

Super PACs, Mr. Walker learned, cannot pay rent, phone bills, salaries, airfares or ballot access fees. They are not entitled to the preferential rates on advertising that federal law grants candidates, forcing them to pay far more money than candidates must for the same television and radio time.

.. All told, as of June 30, the most recent reporting deadline, Republican super PACs and other groups involved in the primary had raised about $256 million, compared with just $78.4 million for the candidates.

.. Most of the candidates — with the prominent exception of Donald J. Trump, who is paying his own way — are now relying to a significant extent on super PACs to communicate with voters on their behalf in the five weeks remaining until the next Republican debate. This stretch, several Republicans predicted, will be a test of how effectively super PACs can prop up candidates who are otherwise limping in the polls, like former Gov. Jeb Bush or Senator Marco Rubio, both of Florida.

.. The super PAC backing Mr. Bush, which raised more than $100 million this spring and summer, twice as much as any other group, is spending $37 million on a last-ditch advertising campaign to introduce him as a proven conservative executive. That sum amounts to three times more than Mr. Bush’s own campaign had raised through the beginning of July, an enormous investment that appears unprecedented for this early in a Republican primary.

“I think Jeb Bush, without a super PAC, would not be doing well at all,” Mr. Backer said. “But $25 million can put out a lot of information to help change people’s minds.”