JIM LEHRER: Finally tonight: two reports about Mexico.
We begin with the state visit by the country's president.
Margaret Warner has that story.
MARGARET WARNER: It was a full-scale White House welcome for Mexican President Felipe Calderon, with all the traditional pomp and color. The leader set a tone of cordial understanding with statements that mirrored each other.
U.S. PRESIDENT BARACK OBAMA: The United States and Mexico are not simply neighbors, bound by geography and history. We are, by choice, friends and partners.
FELIPE CALDERON, Mexican president (through translator): We are friend and partner nations, nations that work together and trade, and that complement each other economically, nations that dialogue and that are intertwined by geography and history.
MARGARET WARNER: But their friendly words couldn't hide the fact that U.S.-Mexican relations are beset by some contentious issues right now, first and foremost, the new immigration law in Arizona. The new statute, signed last month by Governor Jan Brewer, makes it a crime to be in Arizona without proper documentation.
It directs state and local police to enforce it, stopping people and checking documents if necessary. In a country with 12 million illegal immigrants, polls show more Americans support the law than oppose it. But it has sparked protests by people on both sides of the border, especially in Mexico.
Pollster Jorge Buendia in Mexico City says, the Mexican people wanted President Calderon to use this visit to confront the Obama administration on the issue.
JORGE BUENDIA, pollster: They think that Mexican immigrants are not treated fairly, and the Arizona law just reinforces that perception. So, they want the president to be very critical of the way that the U.S. authorities are dealing with this issue.
When they see a U.S. authority a making very critical law against Mexican immigrants, they also think that the president, Barack Obama, is behind it. They don't perceive a clear distinction between the Arizona government, the Congress, or the U.S. presidency.
MARGARET WARNER: The two presidents emerged from their meeting stressing the agreements they had made to cooperate on energy, border security, and other matters. But, not surprisingly, the immigration issue, and in particular the Arizona law, hijacked their post-meeting news conference.
President Calderon hit at it again.
FELIPE CALDERON (through translator): We will retain our firm rejection to criminalize migration, so that people that work and provide things to this nation will be treated as criminals. And we oppose firmly the Arizona law given unfair principles that are partial and discriminatory.
MARGARET WARNER: That brought a direct question to President Obama and an equally critical response.
QUESTION: Thank you, Mr. President.
President Calderon called again the Arizona law discriminatory. You have called it misdirected. Do you agree with him?
BARACK OBAMA: I think a fair reading of the language of the statute indicates that it gives the possibility of individuals who are deemed suspicious of being illegal immigrants from being harassed or arrested.
And the judgments that are going to be made in applying this law are troublesome.
MARGARET WARNER: The president said he had asked the Justice Department to review the law. Then Mr. Obama pivoted to make a pitch for sweeping immigration reform.
BARACK OBAMA: The Arizona law, I think, expresses some of the frustrations that the American people have had in not fixing a broken immigration system, and, frankly, the failures of the federal government to get this done.
MARGARET WARNER: Former U.S. Ambassador to Mexico Jeffrey Davidow isn't surprised that this latest immigration dispute assumed such prominence today.
JEFFREY DAVIDOW, former U.S. ambassador to Mexico: For Calderon, it served a great purpose, in the sense that, if he had come up here, and not mentioned the Arizona law, and made something of a big deal about it, he would, on his return, be put on a spit and roasted slowly by the Mexican public. This is a big issue for them.
MARGARET WARNER: President Obama also lent his support to Calderon on another big issue, the bloody war he and the Mexican army are waging against the country's drug cartels.
It's a war that has triggered a wave of violence, cartel against cartel and the cartels against the authorities. An estimated 23,000 people have been killed since Calderon took office in late 2006.
JEFFREY DAVIDOW: This is a policy that Calderon has been pursuing for three years. He's really tough on it. Somebody called him the Eliot Ness of Mexico. But it's a policy that is being criticized in Mexico, for a variety of reasons, by some of his political opponents and others. And, so, to get a firm statement of support from President Obama is important.
MARGARET WARNER: He got that from the president and a promise to do more on the U.S. end of the drug trade.
BARACK OBAMA: We're working to stem the southbound flow of American guns and money, which is why, for the first time, we are now screening 100 percent of southbound rail cargo. And guided by our new national drug control strategy, we're bringing new approaches to reducing the demand for drugs in our country.
MARGARET WARNER: But, despite the greater cross-border cooperation and U.S. funding support, the Mexicans have a long struggle on their hands, Davidow says.
JEFFREY DAVIDOW: If it were easy, it would have already been done. I think we have to understand this situation in Mexico has taken more than a generation to -- to become ensconced, and it may take as much as a generation to dig it out.
MARGARET WARNER: Drug policy and immigration are likely to be featured when President Calderon addresses a joint session of Congress tomorrow.