President Obama has a penchant for presidential power plays.

He has been following his own playbook since January 2014 when he declared: “I’ve got a pen, and I’ve got a phone” – his promise to do all that he could to bypass Congress – relying on Executive Orders and actions instead of legislation.

Now, a federal appeals court has struck a critical blow against his strategy to unilaterally “change” the nation’s immigration laws.  Monday, a majority of a three-judge panel of the U.S. Court of Appeals for the Fifth Circuit rejected the president’s unprecedented and unlawful power-grab.

The Fifth Circuit ruled that President Obama’s executive overreach that unilaterally rewrote the law without congressional consent is unconstitutional, unlawful, and violates the separation of powers.

This case is about the law, not immigration policy. It is about upholding our Constitution against an imperial presidency.

The court agreed with 26 states in their legal challenge to the President’s lawless Executive action granting legal residency status to 4.3 million illegal aliens. 

The court further agreed with our amicus brief – filed on behalf of 25 Senators, led by Texas Senators John Cornyn and Ted Cruz, 88 Members of the House of Representatives, led by Judiciary Committee Chairman Bob Goodlatte and former Judiciary Chairman Lamar Smith, and more than 100,000 Americans – that this case was not about policy but about the law.

As I argued when I testified before the House Judiciary Committee and we argued in our brief, impatient presidents simply don’t get to change the law. 

The constitutional system is simple. Congress makes the laws.  The President enforces the laws.  And the courts interpret the laws.

President Obama simply can’t use his unelected bureaucratic agencies to rewrite our nation’s laws when Congress chooses not to do so themselves. This responsibility resides with Congress, not the President.

The court cut right through the Obama administration’s main – and specious – argument that his unilateral executive action to “change the law” was not a categorical change but merely the lawful use of prosecutorial discretion.  

The court held that President Obama’s actions were not the exercise of prosecutorial discretion but a series of “mechanical formulae.”  In fact the court found that the Administration “could not produce any” evidence of “an exercise of discretion.”

As we argued in our brief:

“The States are likely to succeed on the merits of their constitutional claim because the [Administration’s] directive violates the Constitution, impermissibly disrupts the separation of powers, and amounts to an abdication of the Executive’s constitutional and statutory duties. [President Obama] unconstitutionally legislated by creating a categorical, class-based program not supported by law or established congressional immigration policy.”

The court agreed. It ruled that President Obama’s actions were “‘manifestly contrary’” to congressionally enacted immigration law.  Of course, President Obama himself admitted on numerous occasions that he “took an action to change the law.” This is something we have long argued – and the courts throughout this case have agreed – he simply cannot do.

The court’s decision in this case is a major victory for the Constitution, the separation of powers, and our system as a nation of laws – not executive fiat.

The Obama Administration has already announced that it will take this fight to the Supreme Court -- preparing to ask the high court to hear this case. We will be there ready to defend the Constitution.

Clearly, reforms are necessary in our immigration laws.  I’m the grandson of immigrants. We are a nation of immigrants.

However, this case is about the law, not immigration policy.  It is about upholding our Constitution against an imperial presidency.

The Constitution prescribes the legislative process. The president doesn’t get to “change the law.” That is for Congress to do.

Jay Sekulow is Chief Counsel of the American Center for Law and Justice (ACLJ), which focuses on constitutional law. He’s a New York Times bestselling author. Jay's latest book “Undemocratic: Rogue, Reckless and Renegade: How the Government is Stealing Democracy One Agency at a Time” (Feb 2) is available now. He hosts "Jay Sekulow Live"-- a daily radio show which is broadcast on more than 850 stations nationwide as well as Sirius/XM satellite radio. Follow him on Twitter @JaySekulow.