The Immigration Reform and Control Act does not preempt state criminal laws for identity theft and fraud for conduct related to obtaining employment, the U.S. Supreme Court ruled March 3 in Kansas v.  Garcia.
IRCA, 8 U.S.C. Sec. 1324a, requires employers to use an I-9 form to verify that prospective employees are legally able to work in the U.S..  IRCA requires employees to provide information for an I-9, including their Social Security number.  It is a federal crime for an employee to provide false information for their I-9.
IRCA also provides that any information “contained in” an I-9 form may not be used for purposes other than enforcing federal immigration laws and may not be used for other “law enforcement purposes.”
Although IRCA makes it a crime for employers to knowingly hire an alien who is not authorized to work in the U.S., it is not a crime under IRCA or any other federal law for an alien-employee to work without authorization.  The Court previously held, in Arizona v. U.S. (2012), that state laws criminalizing an alien-employee from working without authorization are preempted by federal law.
Ramiro Garcia was charged, under Kansas law, with identify theft for using another person’s Social Security number on W-4 and state tax forms which he filled out in connection with obtaining employment at a restaurant.  Garcia was not authorized to work in the U.S.. 
The State originally charged Garcia with also using the Social Security number on his I-9 form, but dismissed that charge.
Garcia argued that his state charges were preempted by IRCA.  He claimed that since IRCA limits use of information contained on an I-9 form – and the Social Security number at issue was on his I-9 – he could not be prosecuted for using the number on tax forms he also filled out for his employer.
The Kansas Supreme Court ruled that IRCA preempted Kansas law on this basis.
In a 5-4 opinion, the U.S. Supreme Court reversed.
The Kansas Court’s interpretation of IRCA was “flatly contrary to standard English usage,” the Court said.  “Taken at face value, this theory would mean that no information placed on an I-9 – including an employee’s name, residence address, date of birth, telephone number, and e-mail address – could ever be used by any entity or person for any reason.”
“It is not customary to say that a person uses information that is contained in a particular source unless the person makes use of that source,” the Court said.  “The mere fact that an I-9 contains an item of information, such as a name or address, does not mean that information ‘contained in’ the I-9 is used whenever that name or address is later” used somewhere else.
IRCA does not require employees to do anything unrelated to work authorization, the Court said. 
“Completing tax-withholding documents plays no part in the process of determining whether a person is authorized to work,” the Court said.  “Instead, those documents are part of the apparatus used to enforce federal state and income tax laws.”
Garcia argued that allowing states to bring prosecutions like his would upset federal law enforcement priorities. 
But “in enacting IRCA, Congress did not decide that an unauthorized alien who uses a false identity on tax-withholding forms should not face criminal prosecution,” the Court said.
“There are now many instances in which a prosecution for a particular course of conduct could be brought by either federal or state prosecutors,” the Court said.  “Our federal system would be turned upside down if we were to hold that federal criminal law preempts state law whenever they overlap.”
In any event, “there is certainly no suggestion that the Kansas” prosecution of Garcia “frustrated any federal interests,” the Court concluded.
Loophole created to allow more prosecutions
Justice Breyer, joined by Justices Ginsburg, Sotomayor and Kagan, dissented.
By enacting IRCA, Congress occupied the narrow field of policing fraud committed to demonstrate work authorization, they said.
The majority opinion undermines the Court’s prior holding in Arizona v. U.S. by opening “a colossal loophole,” they said. 
They said that to let the States prosecute job seekers for putting false information on their tax-withholding forms is, in practical effect, to let the States police the I-9 process.  And policing the I-9 process is what IRCA “expressly forbids,” they said.