Pre-empting a civil rights lawsuit filed by the quarantined nurse, New Jersey has backed off a plan to quarantine all people arriving from West African nations who may have had contact with the ebola virus. Buried in the lede of the New York Times report is this key phrase:

Gov. Chris Christie of New Jersey, in a brief interview, said that he expected her to be transferred Monday morning after doctors and federal officials signed off on the plan.

Why, you may ask, would federal officials have to “sign off” on the plan. The answer, as I’ve discussed in previous posts, is that the Obama Administration has no doubt taken the position that New Jersey’s quarantine are frustrating federal policy. Therefore, under its reading of the Supremacy Clause in Arizona v. United States, state efforts to tighten enforcement by the federal government is unconstitutional.

Here, the Governor backed off in the face of federal pressure, though I had a feeling the federal government may have sued Christie to stop it, if he declined.

This episode, which is not over as other states are considering similar measures, puts into stark contrast the tension between the state police power, and the federal authority to constrain states by setting its own policy.