So as I read the links, I am not seeing where the Border Patrol is being asked to not detain drunk illegal aliens, but rather drunk drivers who are not illegals. In other words, the BP does not have jurisdiction over stopping and detaining Joe Citizen who is driving drunk. Joe Citizen driving drunk is not a Federal crime, I suspect, and as such as Federal law enforcement agency would not have jurisdiction. I would hope that the Border Patrol would stop and detain someone who was here illegally and driving drunk, albeit for the immigration violation.