other things. In addition to the general mistreatment of immigrants, the war with Mexico was roundly criticized in the US by several leaders of both parties.
As I recall, the San Patricios formed several batteries of artillery and put their US training to good effect, greatly helping the Mexican Army.
When captured, those who had deserted before the war started were branded and imprisoned as simple deserters, while those who had left after the war began were traitors and summarily hanged in a very slow and public way.
Scott let Riley go with the branding. They manned one battery of Mexican artillery at Cerro Gordo and then had 6 or 7 guns to defend the convent at Churubusco.
when anti-Catholic/anti-immigrant bigotry was heavily in vogue as Irish (and German) immigration significantly increased. A few interesting facts about the San Patricios (from memory): (1) The highest rate of desertion in US military history was during the Mexican War (something well over 10%) but these guys were among the few executed; (2) both US armies (Taylor and Scott) had some of the more inept generals in our history - Twiggs, Pierce, Pillow, Quitman, among others - who were stone stupid and in some instances bigots, and immigrants were especially badly treated; (3) Scott had most - but not all - of the San Pstricios executed. Among the ones he did not execute was John Riley, the alleged ringleader.