Supreme Court Justice Anthony Kennedy promised in 2010 that there was nothing to fear from independent spending groups that raised unlimited dollars. Because they could not coordinate with political candidates, he wrote in the Citizens United decision, they “do not give rise to corruption or the appearance of corruption.”

In the years since that disastrous opinion, politicians around the country have set out to prove Justice Kennedy wrong by stealthily working with the “independent” groups that raise money on their behalf. The latest to get caught doing so is Gov. Scott Walker, Republican of Wisconsin. According to state prosecutors, he was at the helm of a broad and illegal fund-raising effort that involved coordinating with outside spending groups and even controlling them.

Email messages and other documents released on Thursday as part of a Wisconsin lawsuit show that Mr. Walker and his top aides raised money for the local chapter of Club for Growth, one of the outside groups helping Mr. Walker fend off a 2012 recall attempt at the polls. They then directed that millions of dollars raised by the Club for Growth be transferred to other groups that ran ads in support of Mr. Walker and of Republicans who were the subject of State Senate recall elections in 2011. The groups also ran absentee-ballot drives in some of the recalls.

Mr. Walker and Club for Growth say they did nothing wrong, using the laughable excuse that the television ads were about issues, not about politics. In fact, the ads were overtly political, bashing Democratic candidates who were pushing the recall elections, saying they favored illegal immigrants over returning soldiers in giving out education benefits. But the ads would end with a lawyerly twist: Instead of saying “vote against” the candidate, they would urge viewers to call the candidate and tell him how wrong he was.