According to an article on nytimes.com: “In an expansion of its crackdown on drug cartels, the Obama administration plans to announce Thursday that it will give Immigration and Customs Enforcement agents the authority to investigate drug crimes.”
This is a smart allocation of resources. As opposed to concentrating on apprehending non-criminal aliens, having ICE focus on drug crimes and criminals should help to make us safer, which is the goal of law enforcement agencies. Apprehending dishwashers and factory workers who may have overstayed, entered the US illegally or worked without authorization may be easy work, however it does little to benefit Americans.