President Obama's recent speech fits a historic and racist framework through which we can describe the exclusion and banishment of people with felonies who are detained and deported. Even while some parents of citizens will be eligible for relief, parents with felonies and their families will remain vulnerable.
Children are by definition vulnerable. That's particularly true for girls and boys journeying alone, under unsafe circumstances, often fleeing violence. Mexico and the US have an obligation to apply the international principle of the "best interests of the child" as the gold standard for all dealings with underage migrants.