Article IV, Section 4 of the U.S. Constitution says this: "The United States shall guarantee to every State in this Union a Republican Form of Government, and shall protect each of them against invasion. ... "
So, it can certainly be argued that securing the border is not only a right for the federal government as defined in the Constitution, but is, in fact, a requirement to which it must adhere.
Then there's the "Supremacy Clause" — Article VI, Clause 2 — which establishes that the Constitution and the federal laws made pursuant to it constitute the supreme law of the land. "This Constitution, and the Laws of the United States which shall be made in Pursuance thereof; and all Treaties made, or which shall be made, under the Authority of the United States, shall be the supreme Law of the Land; and the Judges in every State shall be bound thereby, any Thing in the Constitution or Laws of any State to the Contrary notwithstanding," the clause says.
Of course, former President Barack Obama didn't bother to follow the Constitution often, and former President George W. Bush wanted to give the millions of people who entered America illegally a path to citizenship.
But not President Donald Trump. He's backing the Constitution.
On Tuesday night, the Trump Justice Department filed a lawsuit against California, charging that three newly-approved state laws are deliberately interfering with the federal government's task of enforcing national immigration policies. The lawsuit also says California has repeatedly obstructed federal plans to increase workplace enforcement against illegal aliens.
"The Department of Justice and the Trump administration are going to fight these unjust, unfair, and unconstitutional policies that have been imposed on you," Attorney General Jeff Sessions will tell law enforcement officers at the California Peace Officers Association gathering on Wednesday, according to a copy of his prepared remarks. "We are fighting to make your jobs safer and to help you reduce crime in America. And I believe that we are going to win."
The state's Democratic governor, Jerry Brown, responded angrily: “At a time of unprecedented political turmoil, Jeff Sessions has come to California to further divide and polarize America. Jeff, these political stunts may be the norm in Washington, but they don’t work here. SAD!!!”
California has passed a cluster of so-called "sanctuary state" bills; one of the new laws gives illegal workers new protections against federal immigration enforcement actions. "Another state law [known] by critics as the 'sanctuary state' bill protects immigrants without legal residency by limiting state and municipal cooperation with the feds, including what information can be shared about illegal-immigrant inmates," Fox New reports.
A third law gives state officials the power to monitor and inspect immigrant detention facilities either run directly by, or contracted through, the U.S. Department of Homeland Security.
The Justice Department has said it's confident the Constitution's Supremacy Clause gives it broad authority to supersede state laws that it says interfere with its immigration enforcement obligations.
The Trump administration argues that California is overstepping its boundaries.
"The provisions of state law at issue have the purpose and effect of making it more difficult for federal immigration officers to carry out their responsibilities in California," Justice Department lawyers argue in the suit. They also call the new laws an "obstacle to the United States' enforcement of the immigration laws and discriminating against federal immigration enforcement."