In a report on Monday's Rock Center on NBC, correspondent Mike Taibbi described how Mitt Romney's ancestors settled in Mexico during the late 1800's: "Mitt has said and written almost nothing about them over the years. One of his rare quotes, that they left the U.S. to escape persecution for their religious beliefs."
Taibbi then noted: "In fact, Mitt's great-grandfather, Miles Park Romney, led that first expedition to escape not persecution but prosecution for polygamy, what Mormons called 'plural marriage.'" Later, Taibbi cited one of Romney's Mexican cousins on the issue: "Mike, a church school administrator here, says Mitt should just tell the whole story, even about the family's polygamist past that died with the great-grandfather Miles."
Proclaiming that Mitt Romney has "publically ignored" his Mexican roots, Taibbi further asserted: "It's the Romney family's roots in the Mormon religion that remain controversial in Mexico, as in the U.S."
Taibbi observed: "Those strong and persistent anti-Mormon sentiments led to Mitt Romney's "Faith in America" address during his first presidential run four years ago....But for the most part, he hasn't publically discussed his religion in detail."
Following his report, Taibbi and host Brian Williams used Romney's family history to attack his stance on illegal immigration. 
Here is a full transcript of the January 9 report:
10:00PM ET TEASE:
BRIAN WILLIAMS: Tonight on Rock Center, the Romneys of Mexico. As in the same family as Mitt Romney. Tonight, the incredible story of their roots there, the members of the Romney family who are Mexican citizens and how they're watching Mitt Romney's presidential run with a mixture of pride and trepidation.
MIKE TAIBBI: Who do you see yourselves as? Are you Mexican? Are you American? Are you a combination of both or what?
LAYTON ROMNEY: I guess we have to be a combination. I can sing both national anthems and tear up at both of them
10:01PM ET SEGMENT:
WILLIAMS: The voting in New Hampshire begins in a matter of hours. The front-runner is Mitt Romney, considered the favorite. He owns a house in the state, he was governor of neighboring Massachusetts. The people of New Hampshire now get to decide if they're going to be giant killers or help to propel the next nominee of the GOP. Romney is taking fire from his fellow candidates. Today, while talking about health care insurance providers, he said he likes firing people. Then his people spent the rest of the day explaining what he meant.
Whatever the primary outcome, Romney is cemented now as a national figure, and we're going to learn something else about him here tonight. It's about the Romneys of Mexico. His family members who are Mexican citizens, and how fascinating this story of how this family came to be. As Mike Taibbi tells us tonight, it's all part of Romney's roots.
MIKE TAIBBI: This is Romney country, horse and cattle land, rich valleys checkered with cotton fields and rolling peach and apple orchards, small towns nourished by John Deere, Coca-Cola, Chevy. It's a place that values the traits many attached to the candidate they see as the inevitable Republican nominee. A candidate even the high school's kids are excited about. Who would vote for Mitt Romney for president?
GROUP OF STUDENTS: Me!
TAIBBI: But this slice of Romney country is in another country, Mexico. And the voices cheering the loudest for Mitt Romney are Mormons like Mitt, and not just Mormons, but Mormons named Romney. It's a little known fact that there's a whole branch of Mitt's family living right here in Mexico, including his second cousin, Layton Romney. How do you handicap his chances?
LAYTON ROMNEY: I think he has a good chance of getting the nomination.
TAIBBI: Layton is only one of about 40 Romney relatives here, who are descended from religious pioneers who first arrived in 1885. But Mitt has said and written almost nothing about them over the years. One of his rare quotes, that they left the U.S. to escape persecution for their religious beliefs. In fact, Mitt's great-grandfather, Miles Park Romney, led that first expedition to escape not persecution but prosecution for polygamy, what Mormons called "plural marriage." His fifth wife, Hannah Hood Hill later followed in her own harrowing covered wagon journey.
It was the union of Miles and Hannah that planted the Romney family tree in Mexico. Down one branch, mitt's grandfather Gaskell and Mitt's Mexican-born father George, later a two-term Michigan governor who ran for president in 1968 and asserted that because both his parents were American-born, his birthplace didn't matter.
GEORGE ROMNEY: There's no question about my having been a natural-born citizen.
TAIBBI: As the Mexican revolution broke out when George was only 5 years old, his parents moved back to the states to avoid the violence and Mitt himself was eventually born in Michigan. But the other branch of the family, leading down to Mitt's cousins, Layton, Mike and Meredith, stayed behind, their numbers growing. But they don't know Mitt, and Mitt and the media army now shadowing his every move don't know them, not yet.
LAYTON ROMNEY: I don't think it'll bother us too much down here. We're isolated from the rest of the world.
TAIBBI: For now, the Romneys of Mexico enjoy pleasant and productive lives in two remaining settlements, Colonia Juarez and Colonia DuBlan, just 175 miles south of the border. Most of the Romneys, dual citizens, and proud of it. Who do you see yourselves as? Are you Mexican? Are you American? Are you a combination of both or what?
LAYTON ROMNEY: I guess it would have to be a combination. I can sing both national anthems and tear up at both of them.
TAIBBI: The Mexican colonies form a sleepy oasis the Romney ancestors created of stolid homes and green lawns, the thriving century-old school and a gleaming Mormon temple overlooking it all in the shadow of the Sierra Madre mountains. And the Romneys over the generations didn't just establish good lives for themselves and their families here. They pursued lives of good in their Mexican settlements. Good jobs, most of them at Layton's fruit and produce operation called Pacame. In fact, the company is one of the valley's two biggest employers, with pickers and sorters working at several different facilities, more than 6,000 people, locals employed by Pacame. Good old American capitalism at work in Mexico.
But the valley the Romneys call home has not escaped the plague of violence that has scarred so much of this country. During our visit, three drug gang-related murders made the local front pages, nothing extraordinary in northern Mexico. And the Romneys know the dangers all too well. Two years ago, Layton's brother Meredith, a cowboy and cattleman here, was kidnapped at gunpoint and held hostage in a mountain cave for three days until a ransom was paid.
MEREDITH ROMNEY: Seen masked men get out, guns in their hands. I just told my wife, be careful. Something's going down.
TAIBBI: It didn't make big headlines then, but if it happened with Mitt as the nominee or with Mitt as president, it'd be a huge story. Down here it's a story that remains a part of the Romney lore. Carlos Nielsen is a family friend and fellow Mormon. He says he admires the Romneys he knows.
CARLOS: They're honest, hard-working. There's nothing they won't do for you.
TAIBBI: A terrific family, Nielsen told us, with an inspiring history in Mexico, the Romney he doesn't know has publicly ignored.
CARLOS: Has he forgotten where his roots are at? I mean, he needs to look back and be reminded where his roots are at.
TAIBBI: But it's the Romney family's roots in the Mormon religion that remain controversial in Mexico, as in the U.S. Local Catholic pastor, Father David Garcia, says there is mutual respect between the religions but – do you consider Mormons Christians? "No, we don't," he said. Adding, "They don't follow the fundamentals of the Christian faith." North of the border back in October, a Baptist preacher named Robert Jeffress went further.
ROBERT JEFFRESS: Mormonism is not Christianity. It has always been considered a cult.
TAIBBI: The Jeffress cult statement and reaction to it led the news cycle for days.
LAWRENCE O'DONNELL: In an explicit attack on Mitt Romney.
ANN CURRY: His religion is once again drawing attention.
TAIBBI: Those strong and persistent anti-Mormon sentiments led to Mitt Romney's "Faith in America" address during his first presidential run four years ago.
MITT ROMNEY: I do not define my candidacy by my religion. I will serve no one religion, no one group, no one cause, and no one interest.
TAIBBI: And occasionally Mitt's tried humor to soften that distrust. Here, a 2006 radio show quip referencing polygamy during a discussion about same-sex marriage.
ROMNEY: Marriage is a relationship between a man and woman and a woman and a woman . Now, I'm just kidding of course.
TAIBBI: But for the most part, he hasn't publically discussed his religion in detail. Should he have a right to his privacy of how he worships?
LAYTON ROMNEY: Everybody has the right to hold things that they deem sacred and not to have to talk about them.
TAIBBI: But Layton's brother Meredith knows if Mitt wins the nomination the Mormon faith they share will be a headline issue again.
MEREDITH ROMNEY: It shouldn't be but it will be.
TAIBBI: And Meredith says a close look at today's Mormonism will tell an unquestionably good story.
MEREDITH ROMNEY: They'll find that we're a peace-loving people and we believe in God and Jesus Christ as our God and our savior.
TAIBBI: Cousin Mike, a church school administrator here, says Mitt should just tell the whole story, even about the family's polygamist past that died with the great-grandfather Miles.
MIKE ROMNEY: It's written in his great-grandfather's diaries, it's out there for anyone to see. It's an open issue. There's no reason to hide it, there's no reason to cover it up. There's no reason to dodge it.
TAIBBI: Until and unless Mitt Romney connects with his Mexican roots, this place will remain as its been, a thoroughly pleasant place on one level, where friendly high school kids from cattle country are happy to show a rare visiting reporter how to use a lasso, even on his producer, who probably didn't enjoy it as much as everyone else. But if cousin Mitt gets to the White House or even becomes the nominee, there's likely to be a media invasion this taciturn cowboy would find intolerable. And then what?
MEREDITH ROMNEY: Just leave me on the ranch and leave me alone.
TAIBBI: I don't think that's going to happen if he gets the nomination.
MEREDITH: Well, it may not, but then they're going to have to be pretty fast to catch me.
TAIBBI: The finals of a presidential campaign, especially in the new media environment, the 24/7 press attention that no one close to the contestants can evade for long. And what if that avalanche starts rumbling Layton's way?
LAYTON ROMNEY: If that's the case, then we'd have to switch our vote [Laughs].
BRIAN WILLIAMS: You may be the last American welcome down there. Mike, it's a fascinating story. And aside from the political science angle, George Romney's citizenship status and whether that would have survived a challenge, the issue just lying out there, we're in an election year, is immigration.
TAIBBI: Yeah, it's going to happen. Obviously, they have a different point of view on that than does candidate Mitt right now. I mean, he's in opposition to the Dream Act, obviously. He supports a border fence, and his cousins down there say that doesn't make any sense at all. There has to be a way because it's important for people to find a way to work, to get a path, to let them work temporarily at least. And they don't think their cousin has the right point of view. That would be a big issue for them to discuss.
WILLIAMS: And couldn't you make the case the family tree is an aspect of the Dream Act?
TAIBBI: Absolutely. I mean, his father could be the poster boy for the Dream Act.
WILLIAMS: Mike, great piece of reporting, thank you. Welcome back.
- Kyle Drennen is a news analyst at the Media Research Center. Click here  to follow Kyle Drennen on Twitter.