Trump's border wall: What is a national emergency?

Here is a look at the powers that come into play when a president declares a national emergency and just what the law allows him to do.

Can he do that?

The president, at his or her discretion, has the authority to declare a national emergency. Historically, that authority comes from Congress, which by 1973 had enacted more than 470 statutes pertaining to the president's authority during a national emergency.

In 1976, Congress enacted the National Emergencies Act that limited the scope of response to declared states of emergency.
The act:

The incoming chairman of the House Armed Services Committee, Adam Smith, D-Washington, agreed that Trump has the authority to declare an emergency and have the U.S. military build the wall. He said on ABC's "This Week with George Stephanopoulos" that while Trump can do it, such an action would likely be challenged in court.

"Unfortunately, the short answer is yes," Smith said when asked if Trump has the authority to declare a national emergency and build the wall.
"I think the president would be wide open to a court challenge saying, 'Where is the emergency?' You have to establish that in order to do this," Smith continued. "But beyond that, this would be a terrible use of Department of Defense dollars."
What is considered a national emergency?
What constitutes a national emergency is open to interpretation, but generally, it is seen as an event that threatens the security of the people of the United States.

According to the Congressional Review Service, a 1934 Supreme Court majority opinion characterized an emergency in terms of "urgency and relative infrequency of occurrence as well as equivalence to a public calamity resulting from fire, flood, or like disaster not reasonably subject to anticipation."

What powers does a president have when a national emergency is declared?
Through federal law, when an emergency is declared, a variety of powers are available to the president to use. Some of those powers require very little qualification from the president for their use.

The Brennan Center for Justice lists 136 special provisions that become available to a president when he declares a national emergency.

A CRS report states, "Under the powers delegated by such statutes, the president may 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, regulate the operation of private enterprise, restrict travel, and, in a variety of ways, control the lives of United States citizens."

However, under the National Emergencies Act, the president must name the specific emergency power he is invoking.

How can he get funds for a wall by declaring a national emergency? Where does the money come from?

According to U.S. law, a president can divert funds to a federal construction project during a declared national emergency.

In the case of the border wall, the money could come from the budget for the Department of Defense under something called “un-obligated” money. Under federal law, un-obligated money in the Department of Defense's budget may be used by the military to fund construction projects during war or emergencies.

Department of Defense spokesman Jamie Davis said in a statement that, “To date, there is no plan to build sections of the wall. However, Congress has provided options under Title 10 U.S. Code that could permit the Department of Defense to fund border barrier projects, such as in support of counter drug operations or national emergencies.”

Can Congress get around it?

Congress can end a president’s call of a national emergency with a joint resolution. A joint resolution is a legislative measure that requires the approval of both the House and the Senate. The resolution is submitted, just as a bill is, to the president for his or her signature, making it a law.