Since 2001, immigration advocates have pushed Congress to enact the DREAM Act. The bill would give lawful permanent residence status and work authorization to anyone who arrived in this country illegally as a minor, has been in the country for at least five years, was in school or has graduated from high school or served in the military, and was not yet 35 years old. Some version of the bill has been introduced in each Congress, but has usually kicked up such a firestorm of opposition that even its high-level bipartisan support has proved insufficient to get the bill adopted.

But no matter. In 2012 the president unilaterally gave effect to the DREAM Act as if it was law via a memo from his secretary of Homeland Security. Who knew? If the president already had the power to impose the DREAM Act, why all the angst in Congress for over a decade of trying to get the bill passed? Why did the president himself claim in 2011 that he had no such authority?

It is important to trace through the Byzantine web of immigration statutes and regulations to see how pernicious the president’s claim of legal authority really is. The memo relies exclusively on the doctrine of prosecutorial discretion in its directive to immigration officials not to deport the so-called DREAMers. Prosecutorial discretion has typically been used in individual cases, not for a wholesale suspension of the law for an entire class of individuals. But even assuming that prosecutorial discretion can be applied so broadly, the memo goes much further by directing that those who are beneficiaries of this non-enforcement policy be granted both a lawful status and work authorization that the law simply does not allow. Tellingly, it cites no legal authority whatsoever for this extraordinary claim.

Others have tried to find a statutory hook for the President’s asserted authority. One federal regulation, 8 C.F.R. § 274a.12, allows for work authorization for designated classes of aliens. But as the regulation itself acknowledges, those provisions allowing for work authorization must be grounded in statutory authority, and none of the statutes cited as authority for the regulation provide the necessary authority.

There are two plausible statutes cited by the regulation:

8 U.S.C. § 1101 is the “definition” section of immigration law, and many of the authorizations for legal status are made by way of definitional exemptions from the general rule. The term “alien,” for example, is defined as any person not a citizen or national of the United States. The term “immigrant” is defined in subsection (a)(15) as every alien except an alien described in one of 22 separate statutory exemptions. Beyond these carefully delineated exceptions, there is no authority in this statute for the executive branch to grant authorization for legal status.

8 U.S.C. § 1324a deals with employment of illegal immigrants. Like Section 1101, it provides for certain authorizations by way of exemption from the general rule that employing an unauthorized alien is illegal. Section (a)(1) specifically makes it unlawful to hire “an unauthorized alien.” Subsection (h)(3) defines “unauthorized alien” as any alien who is not “lawfully admitted for permanent residence” or an alien “authorized to be so employed by this chapter or by the Attorney General.”

That last phrase, “or by the Attorney General” does the heavy lifting for the president’s assertion of authority for complete discretion to not only decline to prosecute and/or deport illegal immigrants, but to grant them lawful residence status and work authorization. Never mind that with such absolute discretion, none of the carefully circumscribed exemptions would be necessary. And never mind that the much more likely interpretation of that phrase is that it refers back to other specific exemptions in Sections 1101 or 1324a that specify when the attorney general might grant a visa for temporary lawful status.

Article I, Section 1 of the Constitution makes patently clear that “All legislative powers” granted to the federal government “shall be vested in” Congress. And Article I, Section 8, Clause 4 makes clear that plenary power over naturalization is also vested in Congress.

The Court has allowed Congress to delegate much regulatory authority to executive agencies, but requires that Congress provide an intelligible principle pursuant to which the regulatory authority must be exercised. The unfettered discretion that results from the president’s interpretation of Section 1324a(h)(3) runs afoul of the non-delegation doctrine even in its much weakened modern state. That cannot be the right answer in a Constitution devoted to the Rule of Law. The President’s constitutional duty is to “take care that the laws be faithfully executed,” not to rewrite them as he wishes, enforce them only when he wants, and otherwise render Congress superfluous.

Dr. John C. Eastman is the Henry Salvatori Professor of Law & Community Service and former Dean at the Chapman University Dale E. Fowler School of Law. He is also a senior fellow and director of the Claremont Institute’s Center for Constitutional Jurisprudence.