Merida (which was named for the capital of Yucatan, where the relevant meetings were held) was an agreement between Bush and Felipe Calderon for an increased US commitment to fighting Mexico's drug trade.
The US committed $1.4 billion through Merida, but so far we've only actually spent $7 million. One of the specific items that we promised but have so far not delivered is attack helicopters.
More than 10,000 Mexicans have died from drug violence during the past three years.
According to the article, the four countries which receive the most US money for military programs are: