Akin tweeted that statement on Tuesday, and asked for people to retweet if they think "Claire shouldn't put her liberal agenda ahead of the poor economic situation facing Americans!"

McCaskill spoke in March 2011, and said that "the good news is our emissions are way down because of the recession." She clarified that she "didn't mean really good news," but that "emissions are way down because of unfortunately the lack of economic activity that we have had in the last couple of years."

Akin has been the subject of intense media criticism after backing up his opposition to abortion by saying women victims of "legitimate rape" often do not conceive because their bodies have "ways to shut that whole thing down."

Despite that statement, Akin was leading McCaskill in some polls that were being reported on Tuesday.