Iowa City, Iowa – New Jersey Gov. Chris Christie opened a town hall meeting here by invoking an argument that was overshadowed at last week's debate.

During that showdown, as Florida Sen. Marco Rubio and Texas Sen. Ted Cruz faced sharp questions about past conflicting views on immigration policy, Christie stepped in to play the role as an unlikely savior. Candidates are allowed, he said then and repeated Saturday, to shift their views once in a while.

“Isn’t it OK for thinking, breathing adult human beings to change their mind?” said Christie to a crowd of 200 or so in Iowa City.

“I can tell you the things I felt and believed in my 30s, I don’t believe now that I'm in my 50s. We start to think and we learn from life’s experience. That’s why I’m not going to call Sen. Rubio or Sen. Cruz a flip-flopper.”

The night before, at a riverside hamlet about 40 miles down the road, the 500 people who packed a plastics warehouse in Wapello to hear Cruz speak heard roughly the opposite argument.

Cruz has based his campaign on ideological purity, pitching himself as a conservative whose beliefs are consistent and not convenient. The tea party darling urged the voters to ask themselves which of the GOP candidates are "most devoted to conservatism."

"Of all the candidates running, I’m the consistent conservative," said Cruz. "And in my view the stakes are so high we can’t get it wrong this time. We can’t get a candidate who has talked the talk but not walked the walk.”