As I’ve mentioned, the history of the margarita is murkier than the drink itself, so I was pleased to stumble across the following paragraph in David Wondrich’s rigorously researched history of drinks: Imbibe! From Absinthe Cocktail to Whiskey Smash, a Salute in Stories and Drinks to “Professor” Jerry Thomas, Pioneer of the American Bar. The paragraph appears in a section on the Daisy, a drink popular in America before prohibition.
“It’s worth going into this much detail about the Daisy because of something that happened in Mexico while the Great Experiment was running its course in el Norte. First off, in 1939 or thereabouts, the new American-financed gambling and golf resort at Agua Caliente, outside Tijuana, introduced its house cocktail, the “Sunrise Tequila”. Tequila. Lime juice, Grenadine. A little creme de cassis. Ice. Soda. In other words, a tequila Daisy, modern type. Second, a little after repeal, journalists and other travelers who visited Mexico started talking about a “Tequila Daisy,” and in 1936 this even pops up north of the border, in Syracuse, New York, of all places. Unfortunately, nobody bothers to record which kind of Daisy they’re drinking, the old-school one, which was often served in Cocktail glasses with only a minimal amount of fizz, or the new-school one like Agua Caliente’s Sunrise. This is important because of the Spanish word for “daisy”. If they were drinking them old-school, you see, they were drinking tequila, orange liqueur, lime juice (much more common than lemon in Mexico), and maybe a little splash of soda—and ordering them as “margaritas”.
This theory would gibe with my research, which puts the drinks origins well before the commonly espoused mid-century date.