The battle against drug cartels has played a dominant role in U.S.-Mexican relations in recent years. Officials on both sides of the border have said that drugs traveling north from Mexico to consumers in the United States and weapons traveling south from the United States to cartels in Mexico are an increasingly deadly combination.
High-profile cartel takedowns were a hallmark of former President Felipe Calderon's tenure. Peña Nieto has vowed to take a different approach, focusing more on education problems and social inequality that he says fuel drug violence. The details of his policies are still coming into focus, and analysts say his government has deliberately tried to shift drug violence out of the spotlight.
Critics have expressed concerns that Peña Nieto's government will turn a blind eye to cartels or negotiate with them -- something he repeatedly denied on the campaign trail last year. On Tuesday -- two days before Obama's arrival -- his government arrested the father-in-law of Joaquin "El Chapo" Guzman, head of Mexico's Sinaloa cartel and one of the country's most-wanted drug lords.
While both Obama and Peña Nieto have said they're committed to working together on security issues, it's unclear whether the U.S. role will change as Mexico's government shifts its strategy.
The U.S. president has repeatedly said the United States will work to reduce demand for drugs and to stop the illegal flow of weapons to Mexico. But there's one approach he says isn't on the table -- drug legalization.
Speaking at the Summit of the Americas in Colombia last year, Obama said it was reasonable to debate alternatives in the war on drugs, but insisted legalizing drugs is not a valid option in the United States. "I think it is entirely legitimate to have a conversation about whether the laws in place are doing more harm than good in certain places," Obama said. "I personally, and my administration's position is, that legalization is not the answer."
Peña Nieto's take:
Last year, Peña Nieto told CNN that creating more economic opportunities will be Mexico's greatest weapon in the war on drugs. "That, I think, is going to be the best way my government can prevent organized crime," he said. Without jobs and social programs, he added, "millions of my countrymen have no other option than to dedicate themselves sometimes to criminal activity."
Nearly a third of Mexicans surveyed by Pew say Mexico's government is losing ground against cartels, while 37 percent say the government is making progress.
Mexican public opinion is mixed over the U.S. role in the fight against drug cartels, according to the Pew survey. Nearly three-quarters of Mexicans surveyed said they would welcome U.S. assistance in training Mexican police and military personnel. But support for the United States providing money and weapons to Mexican forces has lost some support in recent years, Pew said. In 2011, 64 percent of those surveyed said they backed such a strategy. This year, 55 percent said they supported that approach.