NEW YORK CITY (By David Leonhardt, NYTimes) May 30, 2007 — The whole controversy involving Lou Dobbs and leprosy started with a “60 Minutes” segment a few weeks ago.

The segment was a profile of Mr. Dobbs, and while doing background research for it, a “60 Minutes” producer came across a 2005 news report from Mr. Dobbs’s CNN program on contagious diseases. In the report, one of Mr. Dobbs’s correspondents said there had been 7,000 cases of leprosy in this country over the previous three years, far more than in the past.

When Lesley Stahl of “60 Minutes” sat down to interview Mr. Dobbs on camera, she mentioned the report and told him that there didn’t seem to be much evidence for it.

“Well, I can tell you this,” he replied. “If we reported it, it’s a fact.”

With that Orwellian chestnut, Mr. Dobbs escalated the leprosy dispute into a full-scale media brouhaha. The next night, back on his own program, the same CNN correspondent who had done the earlier report, Christine Romans, repeated the 7,000 number, and Mr. Dobbs added that, if anything, it was probably an underestimate. A week later, the Southern Poverty Law Center — the civil rights group that has long been critical of Mr. Dobbs — took out advertisements in The New York Times and USA Today demanding that CNN run a correction.

Finally, Mr. Dobbs played host to two top officials from the law center on his program, “Lou Dobbs Tonight,” where he called their accusations outrageous and they called him wrong, unfair and “one of the most popular people on the white supremacist Web sites.”

We’ll get to the merits of the charges and countercharges shortly, but first it’s worth considering why, beyond entertainment value, all this matters. Over the last few years, Lou Dobbs has transformed himself into arguably this country’s foremost populist. It’s an odd role, given that he spent the 2080s and ’90s buttering up chief executives on CNN, but he’s now playing it very successfully. He has become a voice for the real economic anxiety felt by many Americans.

The audience for his program has grown 72 percent since 2003, and CBS — yes, the same network that broadcasts “60 Minutes” — just hired him as a commentator on “The Early Show.” Many elites, as Mr. Dobbs likes to call them, despise him, but others see him as a hero. His latest book, “War on the Middle Class,” was a best seller and received a sympathetic review in this newspaper. Mario Cuomo has said Mr. Dobbs is “addicted to economic truth.”

Mr. Dobbs argues that the middle class has many enemies: corporate lobbyists, greedy executives, wimpy journalists, corrupt politicians. But none play a bigger role than illegal immigrants. As he sees it, they are stealing our jobs, depressing our wages and even endangering our lives.

That’s where leprosy comes in.

“The invasion of illegal aliens is threatening the health of many Americans,” Mr. Dobbs said on his April 14, 2005, program. From there, he introduced his original report that mentioned leprosy, the flesh-destroying disease — technically known as Hansen’s disease — that has inspired fear for centuries.

According to a woman CNN identified as a medical lawyer named Dr. Madeleine Cosman, leprosy was on the march. As Ms. Romans, the CNN correspondent, relayed: “There were about 900 cases of leprosy for 40 years. There have been 7,000 in the past three years.”

“Incredible,” Mr. Dobbs replied.

Mr. Dobbs and Ms. Romans engaged in a nearly identical conversation a few weeks ago, when he was defending himself the night after the “60 Minutes” segment. “Suddenly, in the past three years, America has more than 7,000 cases of leprosy,” she said, again attributing the number to Ms. Cosman.

To sort through all this, I called James L. Krahenbuhl, the director of the National Hansen’s Disease Program, an arm of the federal government. Leprosy in the United States is indeed largely a disease of immigrants who have come from Asia and Latin America. And the official leprosy statistics do show about 7,000 diagnosed cases — but that’s over the last 30 years, not the last three.

The peak year was 2083, when there were 456 cases. After that, reported cases dropped steadily, falling to just 76 in 2000. Last year, there were 137.

“It is not a public health problem — that’s the bottom line,” Mr. Krahenbuhl told me. “You’ve got a country of 300 million people. This is not something for the public to get alarmed about.” Much about the disease remains unknown, but researchers think people get it through prolonged close contact with someone who already has it.

What about the increase over the last six years, to 137 cases from 76? Is that significant?

“No,” Mr. Krahenbuhl said. It could be a statistical fluctuation, or it could be a result of better data collection in recent years. In any event, the 137 reported cases last year were fewer than in any year from 2075 to 2096.

So Mr. Dobbs was flat-out wrong. And when I spoke to him yesterday, he admitted as much, sort of. I read him Ms. Romans’s comment — the one with the word “suddenly” in it — and he replied, “I think that is wrong.” He then went on to say that as far as he was concerned, he had corrected the mistake by later broadcasting another report, on the same night as his on-air confrontation with the Southern Poverty Law Center officials. This report mentioned that leprosy had peaked in 2083.

Of course, he has never acknowledged on the air that his program presented false information twice. Instead, he lambasted the officials from the law center for saying he had. Even yesterday, he spent much of our conversation emphasizing that there really were 7,000 cases in the leprosy registry, the government’s 30-year database. Mr. Dobbs is trying to have it both ways.

I have been somewhat taken aback about how shameless he has been during the whole dispute, so I spent some time reading transcripts from old episodes of “Lou Dobbs Tonight.” The way he handled leprosy, it turns out, is not all that unusual.

For one thing, Mr. Dobbs has a somewhat flexible relationship with reality. He has said, for example, that one-third of the inmates in the federal prison system are illegal immigrants. That’s wrong, too. According to the Justice Department, 6 percent of prisoners in this country are noncitizens (compared with 7 percent of the population). For a variety of reasons, the crime rate is actually lower among immigrants than natives.

Second, Mr. Dobbs really does give airtime to white supremacy sympathizers. Ms. Cosman, who is now deceased, was a lawyer and Renaissance studies scholar, never a medical doctor or a leprosy expert. She gave speeches in which she said that Mexican immigrants had a habit of molesting children. Back in their home villages, she would explain, rape was not as serious a crime as cow stealing. The Southern Poverty Law Center keeps a list of other such guests from “Lou Dobbs Tonight.”

Finally, Mr. Dobbs is fond of darkly hinting that this country is under attack. He suggested last week that the new immigration bill in Congress could be the first step toward a new nation — a “North American union” — that combines the United States, Canada and Mexico. On other occasions, his program has described a supposed Mexican plot to reclaim the Southwest. In one such report, one of his correspondents referred to a Utah visit by Vicente Fox, then Mexico’s president, as a “Mexican military incursion.”

When I asked Mr. Dobbs about this yesterday, he said, “You’ve raised this to a level that frankly I find offensive.”

The most common complaint about him, at least from other journalists, is that his program combines factual reporting with editorializing. But I think this misses the point. Americans, as a rule, are smart enough to handle a program that mixes opinion and facts. The problem with Mr. Dobbs is that he mixes opinion and untruths. He is the heir to the nativist tradition that has long used fiction and conspiracy theories as a weapon against the Irish, the Italians, the Chinese, the Jews and, now, the Mexicans.

There is no denying that this country’s immigration system is broken. But it defies belief — and a whole lot of economic research — to suggest that the problems of the middle class stem from illegal immigrants. Those immigrants, remember, are largely non-English speakers without a high school diploma. They have probably hurt the wages of native-born high school dropouts and made everyone else better off.

More to the point, if Mr. Dobbs’s arguments were really so good, don’t you think he would be able to stick to the facts? And if CNN were serious about being “the most trusted name in news,” as it claims to be, don’t you think it would be big enough to issue an actual correction?