State visits to the White House, like today's with Mexican President Felipe Calderon and his wife, Margarita Zavala, are supposed to be carefully choreographed celebrations of a strong bilateral relationship.
But today the uncomfortable topic of immigration reform kept intruding.
Calderon today took the unusual step of criticizing Arizona's new immigration law from the White House -- twice.
At the arrival ceremony this morning on the South Lawn of the White House, Calderon said that cooperation is needed to fix the U.S.-Mexican immigration issue, but "such laws as the Arizona law that is forcing our people to face discrimination. If we are divided, we cannot overcome these problems."
Later in the White House Rose Garden, Calderon voiced his disapproval of the law once again.
"We oppose firmly the S.B. 1070 Arizona law," which he said was "discriminatory."
President Obama concurred and said the law has the potential of being applied in a "discriminatory fashion."
The president said a "fair reading" of the law -- suggesting that he has read the legislation, unlike Attorney General Eric Holder as of last week -- indicates those who are at risk of being deemed possibly illegal could face "harassment" and that the judgments law enforcement would need to make to apply the law are "troublesome."
The Justice Department is looking at the legislation, the president said, to make sure it is consistent with "our core values" and "existing legal precedent."
Obama also said the law expresses some of the frustrations of the American people for a broken immigration system and the failure of the federal government to find a fix
"I'm sympathetic to those frustrations. I share those frustrations," he said.
The law has not yet taken effect, but in Arizona it has resulted in protests and arrests.
Outside the Tuscon office of Sen. John McCain, R-Ariz., three students were arrested and are facing deportation for being in the country illegally.
The debate is intense and is creeping into the economy. The Los Angeles City Council voted last month to boycott all official business in Arizona, prompting Arizona's utilities commission to all but threaten to cut off electrical power to Los Angeles from Arizona power plants that provide a quarter of that city's energy.
"You can't call a boycott on the candy store and then decide to go in and pick and choose candy you really do want," said Gary Pierce, Arizona Corporation Commission Member
The immigration issue kept intruding throughout the day, even at what was supposed to be a sweet stage-managed trip by first lady Michelle Obama and Zavala to a Maryland elementary school that has many students of Central and South American descent.
One young girl, apparently the daughter of an illegal immigrant, expressed her mother's fear to the first lady.
"She says that, um, Barack Obama is taking everybody away that doesn't have papers," the second-grader from New Hampshire Estates Elementary School said.
"Well, that's something we have to work on, right?" Obama replied. "To make sure that people can be here with the right kind of papers, right?"
The second grade student interrupted the first lady's answer to say, "My mom doesn't have papers."
The school's principal told ABC news that the mother is now afraid and neither she nor the school would have any further comment.
Immigration reform advocates said it was the most meaningful exchange of the day.
"This heartbreaking exchange says more about the current state of the immigration debate than the remarks of the two presidents in the Rose Garden," said Frank Sharry, executive director of America's Voice, an organization working for immigration reform. "The little girl wants her mother to have papers, but hears that the president is sending people away who don't have papers. She speaks the truth."
A spokesman for the Department of Homeland Security said the department's investigations into immigration status questions are "based on solid law enforcement work and not classroom Q and As."
"ICE is a federal law enforcement agency that focuses on smart, effective immigration enforcement that prioritizes criminal aliens who pose a threat to our communities," DHS spokesman Matt Chandler said.
In what has become a familiar refrain, President Obama today said he supported comprehensive reform but blamed Republicans for refusing to join the effort.
"I don't expect to get every Republican vote," he said, "but I need some help in order to get it done."
ABC News' Polson Kanneth, Stephanie Z. Smith and Jay Shaylor contributed to this report.