JUDY WOODRUFF: Meanwhile, in Mexico, the drug war continues nonstop. Nearly 30,000 people have been killed since the Mexican federal government took on the cartels four years ago. And it goes on, even as more kingpins have been killed or captured.
Margaret Warner has that story.
MARGARET WARNER: And, for that, I'm joined by Nicholas Casey, a correspondent for The Wall Street Journal in Mexico.
And, Nicholas, welcome back.
NICHOLAS CASEY, The Wall Street Journal: Hi.
MARGARET WARNER: When Secretary of State Clinton was in Mexico last year, she publicly admitted that America's, she said, insatiable demand for drugs is fueling the Mexican drug wars.
Does the Mexican government feel that the U.S. government is doing enough to -- to restrain demand on our side?
NICHOLAS CASEY: Well, I think the Mexican government's big wish is that the U.S. was able to lower that insatiable demand, as Hillary Clinton put it.
Right now, the main effort of the U.S. is to support Mexico as it tries to battle drug traffickers on its own side of the border, whether it's giving Black Hawk helicopters or lots of money. But, of course, you know, underlying all of that is the fact that the -- the problem is that the U.S. wants to have more and more drugs.
And these groups are being funded on the order of billions of dollars by that U.S. demand that's still there and hasn't gotten any less.
MARGARET WARNER: So, you're saying, though, that the U.S. assistance, then, is mostly of a military and law enforcement nature on the Mexican side of the border?
NICHOLAS CASEY: That's what the focus has been on. It's been on helping the Mexicans, whether through the Mexican military or other institutions in Mexico, try to root out the crime organizations that are part of the problem, certainly, and certainly a really big part of it.
They don't have anything to do with the demand, but they're certainly the ones that are supplying the demand, and they're also the ones that are causing a lot of the violence on the Mexican side of the border.
MARGARET WARNER: So, how is -- and I know this is hard to tell, but how is this four-year war on the drug cartels going in Mexico? I notice there have been a number of high-profile either arrests, killings, captures -- captures of -- of some major drug figures.
NICHOLAS CASEY: There have been. One big one happened in the town of Matamoros, which is just across the border from Brownsville, Texas. A man known as Tony Tormenta, who was one of the leaders of the Gulf cartel, literally one of Mexico's most powerful cartels, was killed in a big shoot-out.
That's good news for Mexico. But one of the problems is, is that, as a lot of these major figures are killed, that leads to violence as other groups are trying to get in and take the territory, sensing some sort of weakness.
The death toll right now in Mexico is 31,000 people -- more than that at this point. And that's a really high, high mark right now in Mexico, and it's really taken a lot, its own toll, on sort of public morale in terms of trying to support this war that is going on in their country.
MARGARET WARNER: So, do authorities see any evidence that, when a big figure like one of these gang leaders is killed or captured, that it puts a crimp in the ability of that cartel to do business? Or are they pretty quickly replaced?
NICHOLAS CASEY: Well, they are replaced.
But one thing to keep in mind is that, when you get rid of someone that has all of the connections, and maybe was even one of the founders of a cartel, you can't just swap in someone else and expect the business to work as well.
So, yes, the theory is, is that, by eliminating these top people, they are fundamentally irreplaceable. But someone will try to take that position. The problem is, it doesn't mean the violence is going to go down. In fact, it might mean violence goes up, because there starts to be a power play for who is going to take control of the cartel.
MARGARET WARNER: Now, as you mentioned, there have been 30,000, 31,000 deaths since this campaign, sort of military-style campaign, began.
Where is public opinion in Mexico on this? Do they support this effort?
NICHOLAS CASEY: Well, throughout almost all of Felipe Calderon's reign in Mexico, he has had a lot of support in doing this. People recognized that this problem had gone unaddressed for years.
There was a recent poll, though, that happened, and it showed that about 49 percent of Mexico thinks the drug war is a failure. Although Calderon's ratings are up, that's pretty bad news, because Mexico, to fight this, really needs the support of the people, because there are a lot of deaths involved in this.
And I think that just the amount of casualties that happened in recent years have really eroded, to a degree, what was strong public support in the beginning of this, when the fight began.
MARGARET WARNER: And, briefly, does President Calderon speak out publicly a lot on -- on the importance of this fight and how well it's going? Do they tout, for instance, these recent arrests or killings of major leaders?
NICHOLAS CASEY: They certainly do.
And part of a struggle like this involves the government spending a lot of time trying to explain what it's doing to the people, because this is taking place, not outside of Mexico, but right in the borders of -- of Mexico.
So, certainly they spend a lot of time trying to explain why these captures are important, and, you know, how these casualties are -- are fitting in with the long-term goals that Mexico has of trying to make it a safe country.
MARGARET WARNER: Nicholas Casey of The Wall Street Journal, thank you so much.
NICHOLAS CASEY: Thanks, Margaret.