Rep. Thomas Massie joined Judge Andrew Napolitano on Fox Nation's "Liberty File" to explain why he opposes President Trump's declaration of a national emergency at the southern border.

Massie (R-Ky.) was one of 13 House Republicans to vote with Democrats on a resolution to overturn the declaration, which Trump intends to use to secure funding for his long-promised border wall.

Massie said he's taking serious criticism from his constituents -- Trump won Kentucky's 4th congressional district by 36 points -- but he doesn't want to set a precedent that presidents can declare a national emergency when they disagree with how Congress appropriates funds.

Napolitano agreed and noted that a future Democratic president could declare an emergency on gun control, climate change or health care to circumvent Congress.

"I support the president, but I do not support executive branch overreach," Massie stated.

Despite that, he predicted that the Senate will pass the resolution, Trump will veto it, a veto override will fail in Congress, and the president will prevail in this particular battle.

"If legislators always vote with the president, we have a king. And if legislators always vote with whatever way the wind is blowing that day, we have mob rule. But if legislators always vote with the Constitution, we have a republic."

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