Will debate panel challenge Walker tonight?

There are at least two substantial opportunities to break ground and make news tonight. Who is game?

*  On Walker's absurd and downright inflammatory claim the environment is cleaner now than when he took office. Here are the facts.

*  On his attendance at a pivotal 2007 meeting with influential strategists and funders to take power. Here is the story, citing Reince Priebus and a senior official with the Koch brothers' American for Prosperity.