Romney has been questioned about the Mormon definition of God, polygamy, the location of Jesus' arrival when he returns to Earth, and even a mysterious saying attributed to Joseph Smith Jr. called the "White Horse Prophecy," which some interpret as a prediction that when the American Constitution is hanging "by a thread," a Mormon will rescue the nation. (Romney dismissed it, and church leaders in the past have discounted it, saying it is not doctrine.)

Romney's tendency to gloss over Mormonism's history and distinctive tenets has upset some fellow Mormons. Some said they cringed when Romney said on "60 Minutes," "I can't imagine anything more awful than polygamy."

Tom Grover, 26, a Mormon who is the host of a weekday talk show on politics on radio station KVNU here, said that while he thinks Romney has handled the scrutiny admirably, some of his callers were incensed about Romney's repudiation of his own ancestors' polygamy. The church outlawed the practice more than a century ago, but members are taught to understand that polygamy had a theological and historical context in the church, which Romney's remark ignored.

"That really left a bad taste in people's mouths," Grover said. "That's a tough thing for people to hear when their ancestors sacrificed a lot to live that life. They probably wouldn't bring polygamy back, but they honor the place of it in church history."

Audrey M. Godfrey, a historian who has written books with her husband, Kenneth, said of Romney, "If I were one of his relatives, I would be upset with him."

Another case arose when George Stephanopoulos of ABC News asked Romney about a Mormon teaching that Jesus will come to the United States when he returns to reign on Earth. Romney responded that the Messiah will return to the Mount of Olives in Jerusalem, "the same as the other Christian tradition."

Grover said some of his radio listeners were astounded.

"They were just in disbelief, saying, 'That's not true; Jesus is coming back to Missouri,"' Grover said. "It's the LDS Church's 10th article of faith that Zion will be built upon the American continent."

While Mormons tend to be conservative on social issues, Romney has taken some positions that are more conservative than those of his own church.

LDS teaching allows abortion in cases of rape, incest and medical opinion that severe defects will prevent the fetus' survival beyond birth, and to protect the health of the mother. The church has no position on embryonic stem-cell research. Romney has in the last few years shifted to embrace an anti-abortion, anti-stem-cell research, anti-gay agenda.

Some more liberal Mormons said in interviews that they were dismayed that he appeared to be both pandering to the right and compromising his integrity.