MADISON, Wis. (AP) — For more than three years Republican Gov. Scott Walker avoided political fallout from a criminal investigation that ensnared six of his former aides and associates. But with Walker up for re-election this year, and considering a run for president in 2016, questions are intensifying over how much he knew about illegal campaign activity going on in his county executive office as he launched his bid for governor. Democrats are trying to use embarrassing emails that were part of 28,000 pages of documents released Wednesday to liken his woes to those faced by other embattled Republicans like New Jersey Gov. Chris Christie. But Walker backers say it's all much ado about nothing given that Walker was never charged with wrongdoing.