"We're winning the white vote. We're not doing so hot with the rest of a diverse nation," he told reporters Friday. "We have to adapt or die."
Paul offered the dinner audience a combination of his own brand of red meat flavored with wry humor in a 20-minute talk.
Why, Paul asked, can't President Barack Obama find money for air traffic controllers or maintaining White House tours? Why not cut a program to study rattlesnake behavior towards squirrels? Or studying the collective action of fish? "There's hundreds of these," Paul maintained.
He skewered Clinton, a possible 2016 rival. "They were pleading for security and got nothing," he said of the months leading up to the Sept. 11, 2012, terror attacks in Benghazi, where four Americans were killed. Her actions, Paul said, "should preclude her from holding higher office."
That got a standing ovation from the crowd, which cheered Paul loudly and often. "We're ready for change, and people are looking for some middle ground. He's a good contender," said Mickey Johnson, a Waterloo, Iowa, dental hygienist.
Paul's drive for inclusion could cause trouble with staunch conservatives who control the Iowa Republican Party, as well as much of the national party apparatus.
During his meeting with pastors, for instance, the subject of traditional marriage came up. Paul supports the notion that a marriage is between a man and woman, but he also believes it's up to individual states to define marriage.
While the pastors uniformly praised Paul, some were wary. "That's one area where I have some questions," said Brad Cranston, director of Iowa Baptists for Biblical Values.
Paul also is wrestling with how to handle his father's fervent supporters. Former Rep. Ron Paul, R-Texas, has an avid following in Iowa — they virtually control the state Republican Party machinery — but the son has some differences from the father.