DeMint's Creative Poll Watching

I just got a fundraising e-mail from Jim DeMint's Senate Conservative Fund touting the prospects of Ron Johnson against Russ Feingold. All well and good except DeMint proudly mentions that Johnson is in a statistical dead heat in a Rasmussen poll that has him up by one. While true that two of the three other polls also feature a dead heat, they also show Feingold is up by two. The third poll has Feingold up by five.