WASHINGTON (AP) — Wisconsin Governor Scott Walker is dismissing as "old news" the thousands of internal documents released last week that suggest former aides routinely mixed campaign and official Milwaukee County business. Walker was county executive when he was running for governor. Six former aides and associates have been convicted, but Walker has not been charged with any wrongdoing. Walker addressed the issue for the first time publicly during Saturday's meeting of the National Governors Association in Washington. Walker says that while the investigation involving him is closed, New Jersey Governor Chris Christie's problems are, in Walker's words, "just beginning." Both Republicans are considering presidential runs. State and federal authorities are probing the Christie administration for days-long traffic gridlock at the George Washington Bridge and whether it was political payback against an adversary.