Pennsylvania Sen. Pat Toomey, one of 12 Republicans to vote with Democrats against President Trump's declaration of a national emergency to secure border wall funding, explained his vote Sunday.

Toomey said Trump had used the National Emergencies Act of 1976 in a way not normally seen, and that his vote was not a rebuke of the president's call for a wall and strict border security.

"The president came to a different conclusion about the Constitution and the law," Toomey said on NBC News. "So did three-quarters of my Republican colleagues."

"We support the wall funding, and if we did have the votes to override the president's veto, he'd still be able to build the wall," Toomey said.

Toomey said his concern was that, under the separation of powers, it is unclear whether a president should be able to "overturn the rejection of a funding proposal" through executive order.

Toomey previously voted in favor of $18 billion to be spent on a border barrier, tweeting that he "will continue to support [Trump's] sensible efforts to secure the southern border."

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Toomey said that both his argument and Trump's argument on the matter are "plausible" under the Constitution.

He added that his Democratic colleagues who voted to rebuke Trump were not making a constitutional argument as he and the other 11 Republicans were.

"They're very happy to poke Trump in the eye," he said, adding that President Obama may have also stretched the bounds of executive power through his multiple "recess appointments," institution of DACA and the some of the ways that ObamaCare was implemented.

Trump blasted those who voted against the emergency declaration in multiple tweets over the past few days. 

White House counselor Kellyanne Conway spoke about the border wall funding demands, telling Fox News that Trump will continue "doing what he is doing."

"He can use as you know, start with 1.75 billion in the original bill. Added to that the asset forfeiture money from treasury. Drug money committed at DOD can go here. After he taps into that roughly 4.45 billion, the military construction projects, another 3 billion plus and change there," she said.

Watch that interview below. 

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