Rep. Ted Lieu (D-CA) on Sunday challenged Donald Trump's notion that the U.S. Constitution is the "dumbest" law because it gives non-citizens the right to due process.

In a tweet Sunday morning, Trump complained that the current immigration system is too slow at deporting undocumented immigrants.

"When people come into our Country illegally, we must IMMEDIATELY escort them back out without going through years of legal maneuvering," Trump wrote. "Our laws are the dumbest anywhere in the world. Republicans want Strong Borders and no Crime. Dems want Open Borders and are weak on Crime!"

When people come into our Country illegally, we must IMMEDIATELY escort them back out without going through years of legal maneuvering. Our laws are the dumbest anywhere in the world. Republicans want Strong Borders and no Crime. Dems want Open Borders and are weak on Crime!

— Donald J. Trump (@realDonaldTrump) June 30, 2018

Lieu fired back in a tweet of his own by explaining that the president had effectively called the U.S. Constituion the "dumbest" law.

"The 'dumbest' law you refer to is called the United States Constitution," Lieu said. "Specifically the 14th Amendment which provides due process to all persons, not just citizens."

"You took an oath to the Constitution at your relatively small inauguration, remember?" the congressman added.

Dear @realDonaldTrump: The "dumbest" law you refer to is called the United States Constitution. Specifically the 14th Amendment which provides due process to all persons, not just citizens.

You took an oath to the Constitution at your relatively small inauguration, remember? https://t.co/T2yGDC1Nt2

— Ted Lieu (@tedlieu) July 1, 2018