Cinco de Mayo gained its first popularity in the U.S. in the 1950s and 1960s, partly because of an outpouring of brotherly love, Alamillo says.
"The reason it became more popular [in the U.S. during that time] was in part because of the Good Neighbor policy," he said, referring to a U.S. government effort at the time to reach out to neighboring countries.
"Cinco de Mayo's purpose was to function as a bridge between these two cultures," Alamillo said.
The holiday's popularity really grew in the 1960s, when Chicano activists embraced the holiday as a way to build pride among Mexican-Americans, Alamillo says.
In 1862 a Mexican militia led by General Ignacio Zaragoza defeated the far better equipped French expeditionary forces.
Emperor Napoleon III sent French troops to Mexico to secure dominance over the former Spanish colony and install one of his relatives, Archduke Maximilian of Austria, as its ruler.
Zaragoza won the battle, but the Mexicans ultimately lost the war. Maximilian was Mexico's emperor for three years before the country reclaimed its independence.
Still, victory at the Battle of Puebla carries a strong anti-imperialist message that resonates with many Mexican-Americans, experts say.
"As a community we are tough and committed, and we believe that we can prevail," said Robert Con Davis-Undiano, a professor of Chicano studies at the University of Oklahoma in Norman.
"That was the attitude of the ragtag Mexican troops who faced and defeated the French in Puebla," he said.
"And Mexican Americans, other Latinos, and literally everyone can feel proud and motivated by that message."
At the same time, Cinco de Mayo was transformed from a strictly nationalist celebration to a bicultural event that expressed the Mexican-Americans' identity, Washington State's Alamillo says.
"It allowed for Anglo-Americans to partake in and learn about Mexican culture through Cinco de Mayo," Alamillo said. (See a gallery of Mexico photos.)
"Mexican Americans by this point were interested in building this relationship, because they were asking for certain political demands and for more resources for the community.
"It became a really interesting negotiation festival in a lot of ways."
From Culture to Commercialism
Then came the 1980s, and the commercialization of Cinco de Mayo.
This, Alamillo says, is when the meaning of the holiday changed from community self-determination to a drinking holiday for many people.
He says American corporations, particularly those selling alcohol, were eager to tap into the expanding Hispanic population in the U.S.
"It's not just the large number of the Hispanics, but also that it's a very young population that is particularly receptive to advertisers," Alamillo said.
"Cinco de Mayo became a vehicle to tap into that market."
Davis-Undiano, the University of Oklahoma professor, still sees Cinco de Mayo as a positive force that can bring Latinos and non-Latinos together, especially at a time when tensions surrounding the illegal immigration debate run high.
(Related news: "U.S. Immigration Law Could Harm Desert Animals, Critics Say.")
"I'm convinced there is a lot of unprocessed anxiety among non-Latinos concerning what changes that will come with a much larger Latino population," he said.
"Cinco de Mayo gives everyone a chance to feel like a single community."
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