Prof. Hayes-Bautista notes that the celebration of the holiday has much to do with the American Civil War. On the radio broadcast, he goes into somewhat more detail than in the UCLA Newsroom write-up and video.
Also on the broadcast, he was followed by Gustavo Arellano, author of the ¡Ask a Mexican! column of the OC Weekly. Arellano was the UCLA commencement speaker in June 2010. (See http://www.youtube.com/watch?v=riTZrznZWdE.) Arellano gives his own perspective on the broadcast and notes that the battle of May 5, 1862 which the holiday celebrates – in which Mexicans defeated the French – was followed by a later French victory and that Mexican culture and food has remnants of the subsequent period of French rule. You can hear the interview below:
Note: The full broadcast is at http://www.kcrw.com/media-player/mediaPlayer2.html?type=audio&id=ww120503cinco_de_mayo_and_ot