Yesterday the U.S. Justice Department warned that the federal government may cancel all flights out of Texas if the state legislature approves a law aimed at preventing the Transportation Security Administration from groping airline passengers without probable cause. H.B. 1937, which was approved unanimously by the state House of Representatives and is being considered by the state Senate, applies to any government employee who, without probable cause to suspect a crime has been committed, "performs a search for the purpose of granting access to a publicly accessible building or form of transportation" and in the process "touches the anus, sexual organ, buttocks, or breast of another person including through the clothing, or touches the other person in a manner that would be offensive to a reasonable person." Such a search would be a misdemeanor punishable by a $4,000 fine and up to a year in jail. In a letter (PDF) to the leaders of the state legislature, John E. Murphy, the U.S. attorney for the Western District of Texas, says:

The effect of this bill, if enacted, would be to interfere directly with the Transportaion Security Administration's…responsibility for civil aviation security….Congress has directed the Administrator of the TSA to take "necessary actions to improve domestic air transportation security"…and directed him to prescribe regulations to protect passengers and property on an aircraft…against an act of criminal violence or aircraft piracy."…Congress has directed TSA to provide for "the screening of all passengers and property…before boarding," in order to ensure that no passenger is unlawfully carrying a dangerous weapon, explosive, or other destructive substance….If the Administrator determines that "a particular threat cannot be addressed in a way adequate to ensure…the safety of passengers and crew of a particular flight," he "shall cancel the flight or series of flights."… HB 1937 would conflict directly with federal law….Under the Supremacy Clause of the United States Constitution, Texas has no authority to regulate federal agents and employees in the performance of their federal duties or to pass a statute that conflicts with federal law. If HB 1937 were enacted, the federal government would likely seek an emergency stay of the statute. Unless or until such a stay were granted, TSA would likely be required to cancel any flight or series of flights for which it could not ensure the safety of passengers or crew.

State Rep. David Simpson (R-Longview), H.B. 1937's chief sponsor, replies:

Either Texas backs off and continues to let government employees fondle innocent women, children and men as a condition of travel, or the TSA will cancel Texas flights. The Federal Government showed its willingness to bully the State of Texas if attempts to protect passengers from being forced to give up constitutional rights are not dropped. The DOJ attempted to justify their action by an appeal to the Supremacy Clause of the United States Constitution and by claiming that the bill "would conflict directly with federal law." However, HB 1937 already grants a defense to prosecution for an offense that the actor performed pursuant to and consistent with an explicit and applicable grant of federal authority that is consistent with the United States Constitution. "The bill clearly states that an agent is exempt from prosecution as long as a constitutionally sanctioned federal law directs them to perform the invasive, indecent groping searches-including touching breasts, sexual organs and buttocks," noted [Simpson]. "Instead of threatening to shut down flights in Texas, why doesn't the TSA just show us their statutory authority to grope or ogle our private parts?" asked Simpson.

I noted Simpson's bill, the first of its kind to be approved by a state legislative chamber, earlier this month. More on TSA pat-downs here.