IOWA FALLS, Iowa — Republican presidential candidate Mitt Romney promised Thursday he won't be a "shrinking violet" when it comes to defending his Mormon faith during the campaign, but he said he still isn't sure giving a major speech about his beliefs is a good idea.

Romney spent the day campaigning around the state in anticipation of Saturday's non-binding straw poll of Iowa Republicans. He spoke to the Deseret Morning News during the drive between two small farm communities north of Des Moines.

"I guess people who watch the normal interviews and TV debates see me in my normal nice guy mode," the former leader of the 2002 Winter Olympics in Salt Lake City said. "But I also have backbone. I'm no shrinking violet. And if someone questions my commitment to my faith or my family, I'll respond with strength."

That's what Romney said he did last week, when a conservative radio talk-show host in Iowa accused him of distancing himself from The Church of Jesus Christ of Latter-day Saints to attract conservative voters.

Although the sometimes heated exchange between Jan Mickelson at WHO-1040 and the candidate occurred off the air, the station tapes interviews with presidential candidates and didn't stop the cameras during commercial breaks.

The videotape has become something of a hit on the Internet after being posted to YouTube by the campaign, where it has been viewed more than 172,000 times. The controversy, reported Tuesday by the Deseret Morning News, was featured in a column in The Des Moines Register Thursday.

Romney, who told Mickelson in the exchange that he was proud of his faith and didn't appreciate his beliefs being attacked, said he's getting an "overwhelmingly positive response" from the public. "They're saying, 'I'm glad you showed your strength and your backbone,"' Romney said, explaining he was reacting to the suggestion "that I somehow wasn't faithful to my church.

"I am not a 'cafeteria' Mormon. I accept my faith. I love my faith. I will not distance myself from it in any way, shape or form. I am not perfect. I don't know everything about my church. I have not lived all the doctrines perfectly," Romney said. "I'm not going to give you a list of my personal failings, but I can tell you I believe my church and try to live by its teachings."

Marc Hansen, a columnist for The Des Moines Register, said the videotape offered viewers a chance to see "a side the candidate should channel more often. ... He's quick on his feet. He's showing some fire, some passion, some spontaneity."

But Romney still wasn't ready Thursday to commit to giving what pundits have called the "JFK speech," to outline his beliefs and address questions raised about Mormonism. John F. Kennedy, who became the country's first Catholic president in 1960, gave a speech shortly before the election to dispel any notion his administration would be controlled by the pope.