Paul's tour includes stops in Des Moines, Davenport, Cedar Rapids, Cedar Falls, and Mason City.

An NBC poll released Friday showed Paul in second place in the Hawkeye State, his 21 percent just 2 points behind front-runner Mitt Romney.

Paul's son Rand has spoken in praise of his father's campaign during radio and television appearances in recent months. Over Christmas, the Paul campaign released a Christmas ad in early voting states featuring the Kentucky senator.

"The Tea Party began as a protest against politicians who supported more debt and bigger government," Rand says, flanked by a Christmas tree and seasonal decorations. "My father, Ron Paul, stood against the establishment and against government bailouts. He’s always stayed true to his principles and convictions. He won’t falter, he won’t bend, and he will restore what made America great."