The irony of the whole Iowa push polling mess – and Romney blaming it on the McCain-Feingold campaign finance law is that it was John McCain who was victimized by push polling in South Carolina in 2000:

In South Carolina, Bush Republicans were facing an opponent who was popular for his straight talk and Vietnam war record. They knew that if McCain won in South Carolina, he would likely win the nomination. With few substantive differences between Bush and McCain, the campaign was bound to turn personal. The situation was ripe for a smear.
It didn’t take much research to turn up a seemingly innocuous fact about the McCains: John and his wife, Cindy, have an adopted daughter named Bridget. Cindy found Bridget at Mother Theresa’s orphanage in Bangladesh, brought her to the United States for medical treatment, and the family ultimately adopted her. Bridget has dark skin.
Anonymous opponents used “push polling” to suggest that McCain’s Bangladeshi born daughter was his own, illegitimate black child. In push polling, a voter gets a call, ostensibly from a polling company, asking which candidate the voter supports. In this case, if the “pollster” determined that the person was a McCain supporter, he made statements designed to create doubt about the senator

Push polling undid McCain, will it make Romney?