What would happen if President Donald Trump declared a national emergency in order to build a southern border wall?

The president is currently exploring the idea of declaring a national emergency so that he can build the wall without the approval of Congress. As the partial government shutdown heads into its third week, Congress is stuck at an impasse as Democrats say they will not give Trump any of the $5.7 billion he has requested for the wall.

Trump told reporters Friday that he is open to using emergency powers to circumvent Congress, stating, “We can call a national emergency and build it very quickly. It’s another way of doing it.” (RELATED: Trump Open To Using Emergency Powers To Build Wall)

He reiterated the idea Sunday, adding that he would wait and see what negotiations yielded over the next “few days.”

Trump’s words have sparked debate as to whether or not he has the authority to declare a national emergency on the border.

Democratic California Rep. Adam Schiff called the idea a “nonstarter” Sunday, asserting, “If Harry Truman couldn’t nationalize the steel industry during wartime, this president doesn’t have the power to declare an emergency and build a multibillion-dollar wall on the border.”

The president has an unlikely supporter in Democratic Washington Rep. Adam Smith, who says that the president “can declare an emergency.” Smith did concede Monday on CNN that he thinks any such declaration would be met with significant legal challenges.

Congressman Adam Smith, the new Chairman of the House Armed Services Committee, just stated, “Yes, there is a provision in law that says a president can declare an emergency. It’s been done a number of times.” No doubt, but let’s get our deal done in Congress! — Donald J. Trump (@realDonaldTrump) January 7, 2019

Legal experts similarly told NBC that Trump could declare a state of emergency under The National Emergencies Act — which grants the president a set of special executive powers, including but not limited to the ability to “seize property, organize and control the means of production, seize commodities, assign military forces abroad, institute martial law, seize and control all transportation and communication.”

Congress also has the ability to pass a joint resolution rebuking the president’s declaration. The president would therefore have to convince Congress that the surge of illegal immigration on the border constitutes an “emergency.”

Another challenge facing the president is that he can only use previously earmarked funds in order to build the wall. But federal law allows the military to complete “construction projects” using un-obligated funds from the Department of Defense (DOD) budget during a national emergency.

“My instinct is to say that if he declares a national emergency and uses this pot of unappropriated money for the wall, he’s on very solid legal ground,” Harvard law professor Mark Tushnet told NBC News.

Legal analyst Joe DiGenova pointed Monday to the same unmarked pot of DOD money on WMAL’s “Mornings on the Mall.”

“The real issue is once the president declares an emergency, which he has the power to do, where does he get the money to implement it?” DiGenova said. “There is unspent money in the Department of Defense budget of about $100 billion.”

“It’s sitting there waiting for contracts,” he continued. “He does have the authority to use that money.”

The president would be able to declare a national emergency, but he would certainly have to fight a number of congressional and legal challenges to keep the order in place and build the wall.

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