Scott Walker has said that he campaigned on his plan to curtail collective bargaining rights for public employees. Politifact calls this claim false. National Review's Matthew Shaffer says it's true, or truthy enough for him:
MYTH: Walker blindsided everybody.
FACT: During his campaign, Walker was explicit about his intention to cut wages and benefits and generally take on the public sector. He ran on it. He had a reputation for anti-public-sector action as county executive in Milwaukee. During his campaign, the unions themselves issued flyers warning that he would take away collective-bargaining rights if elected. He never denied that he would take on collective-bargaining privileges — we would have heard all about it if he had.
Nobody is denying that Walker promised to reduce benefits. The question here is Walker's claim that he detailed his curtailment of collective bargaining rights during the campaign. Shaffer's evidence here is that unions accused Walker of wanting to do this, and he never denied it.
Obviously, being accused by your opponent of wanting to do something is not the same as promising to do it yourself. Otherwise, President Obama could claim a mandate from the 2008 election to impose white slavery. There were flyers accusing him of it! He never denied it! He could even say that he ran on a platform of imposing white slavery in 2008, and National Review would have defended him.