Rep. Justin Amash, R-Mich., argued Sunday that President Trump's declaration of a national emergency on the southern border falls outside of the president's constitutional limits.

The congressman told CNN's Jake Tapper on "State of the Union" that a national emergency declaration violates core constitutional principles of separation of powers and warned his fellow Republicans against setting this legal precedent.

"We have a separation of powers under the Constitution. The legislative branch, Congress handles legislative powers. And this is something that we have had going through Congress for the past several years," Amash told Tapper. "There's been discussions about border wall or fencing. We've passed appropriations bills. The president has signed the bills. He hasn't vetoed the bills. If he wanted to say that there was a crisis, he could have vetoed the legislation. He's never vetoed appropriations."

"I think the president is violating our constitutional system. And I don't think Congress can grant legislative powers to the president by statute. You can't just pass a statute that says the president now has appropriations power and bypass Congress," he added.

House Democrats passed a resolution last week to block Trump from using executive power to declare a national emergency with the help of 13 Republicans. The Michigan lawmaker was the only Republican to co-sponsor the bill. The bill is widely expected to be vetoed by Trump should it get to his desk and the bills ability to get to veto-proof status is questionable at best.