Biden was in Mexico Monday before traveling Tuesday to Honduras as part of his discussions with Central American leaders.
In Mexico City, Biden said he told Mexican President Felipe Calderon the "United States can do more" to stop drug-related criminal activities such as money laundering "and I acknowledged that to Calderon, and there is more Mexico can do" as well.
Biden said he and the candidates wanting to succeed Calderon discussed the decriminalization of illegal drugs, with the vice president saying issue merited discussion but he opposed the idea.
"It impacts on a country's productivity. It impacts on the health costs of that country. It impacts on mortality rates. It's worth discussing," Biden said. "But there is no possibility that the Obama-Biden administration will change its policy on legalization."
Biden met with the three people who hope to succeed Calderon as the country's president. Calderon is barred by law from seeking another term. Biden met with Andres Manuel Lopez Obrador of the Party of the Democratic Revolution, Enrique Pena Nieto of the Institutional Revolutionary Party and Josefina Vazquez Mota of the National Action Party.
When asked if there would be any change in U.S.-Mexico relations with any of the candidates, Biden said, "No, and I'm not being flippant about it, but no."
Later, after visiting the shrine of the Virgin of Guadalupe, and the Antigua Parroquia de Los Indios (Old Church of the Indians), part of the pilgrimage for millions of Catholics, Biden said he didn't want to discuss his meetings with the candidates, just take in the sites.
"I rather not talk about the candidates," said Biden. "I had a wonderful day with the candidates, but I had a better day here. I would have come just for this. … It's a great treasure."
Biden, who's Catholic, said his mother was a "great devotee of the blessed mother."
"My only regret is that she's not here," he said.
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