Trump has threatened to declare a national emergency to build a wall. Is that legal? [PBS Newshour]

Emergency powers are usually used to address political crises in other nations such as the systemic violation of human rights, war, or a serious threat of abuse of weapons of mass destruction or nuclear weapons, said Sahar F. Aziz, director of the Center for Security, Race and Rights at Rutgers Law School in an email to PBS NewsHour.

For example, Aziz said, emergency powers were invoked in response to opposition to stabilization efforts in the Balkans in 1997 and the wars in Syria and Yemen in 2012.

The president doesn’t necessarily have to prove there has been a major change in circumstances at the southwest border. But compared to the ways emergency powers have previously been invoked, a declaration of an emergency by Trump “may be unprecedented and an abuse of authority for a purely political purpose as opposed to any purported national security purpose,” Aziz said.

— Read the full article published on January 10, 2019 on the PBS Newshour here.