In U.S. Senator Ron Johnson's latest ad, they're apoplectic at the notion of a Political Action Committee (PAC) spending "nearly half" of their contributions on fundraising for more contributions.
Although this may seem like a lot, it depends on how you look at it. If you spend six dollars to bring in ten (a four dollar net gain), it's better than spending one dollar to bring in three (a two dollar net gain).
Plus, only a small percentage of fundraising appeals yield money. However, the 95% of the people that just read the fundraising letter or web ad and don't give are still armed with the information that it contained and are more likely to vote and volunteer their time. All this is part of the calculation.
That is why you see other Wisconsin politicians, including many that Ron Johnson campaign's with frequently, typically not only spend over half but around two-thirds of their funds on fundraising (see above).
Plus, Ron Johnson himself, has spent nearly half in past years on fundraising for his PAC. In 2012, for example, Ron Johnson spent 44% on fundraising and 14% on administration. This left much less than 50% for contributions to other candidates-- the big sin he is accusing Russ Feingold of committing.