BillD: I had to say reportedly because I haven't seen it - here's the quote from the Economist:

"And fighting pretty dirty. One of Mr Obama's television ads warns, falsely, that Mr McCain plans to cut public pensions in half. Another spot, in Spanish, suggests that Mr McCain is a bigot. The ad blames "John McCain and his Republican friends" for the failure of immigration reform, and implies that he agrees with Rush Limbaugh, a rabble-rousing talk-show host who once referred to "stupid, unskilled Mexicans". In fact, Mr McCain was one of the two main sponsors of immigration reform, a brave stance that earned him the enmity of Mr Limbaugh."

http://www.economist.com/world/unitedstates/displaystory.cfm?story_id=12341739

It may be a creative interpretation - I don't know.