The primary error in this line of thinking is to draw parallels between a racial issue and a drug issue. In the case of the racial issue, the federal government

The primary error in this line of thinking is to draw parallels between a racial issue and a drug issue. In the case of the racial issue, the federal government was acting on the behalf of a portion of its citizenry, and against the will of a smaller portion of citizens; in this case the federal government would find itself on the right side of history. In the drug case, the federal government is acting against the expressed will of a larger portion of citizenry, to the extent that many of those citizens have expended considerable effort to pass legislation contrary to the federal government's enforcement; in this case, I think it is quite likely that the federal government will find itself on the wrong side of history. Merely drawing parallels from issues of states' rights versus federalism in the past isn't very enlightening. You have to consider each issue on its own merits. That "righteous anger" isn't because this is simply a states' rights issue; rather, it's because the federal government is acting against the wishes and welfare of the citizens of states, and it is not doing so to protect the interests of some demographic group of victims.