AILSA CHANG, HOST:
There is perhaps no phrase more compelling in Washington than the words national security. We have the National Security Council, the National Security Agency. And especially in the Trump administration, we have seen a spate of presidential actions from travel bans to tariffs all done in the name of national security. Our own national security correspondent David Welna takes a closer look.
DAVID WELNA, BYLINE: To understand just how widely the national security blanket has spread during the Trump administration, take a listen to Commerce Secretary Wilbur Ross justifying new punitive tariffs on imports last month before the Senate Finance Committee.
(SOUNDBITE OF ARCHIVED RECORDING)
WILBUR ROSS: This administration is standing up for American families, American businesses and American workers by taking action to reduce imports that threaten our national security.
WELNA: Pennsylvania Republican Pat Toomey wasn't buying it.
(SOUNDBITE OF ARCHIVED RECORDING)
PAT TOOMEY: I wish we would stop invoking national security because that's not what this is about. This is about economic nationalism.
WELNA: When the rules for international trade finally got hammered out a quarter of a century ago, Rufus Yerxa was a top U.S. negotiator. While national security did figure in those talks, he says...
RUFUS YERXA: The notion of a national security restriction was pretty clear. It related to situations of war or an international economic emergency that would justify some narrow use of trade measures to cover essential security interests.
WELNA: Other nations have tried using national security to protect home industries. University of Notre Dame law professor Diane Desierto says Sweden slapped quotas on imported shoes in 1975, arguing a domestic shoe industry was essential should there be a war.
DIANE DESIERTO: The notion of national emergency or national security, it's part and parcel of every legal regime, every constitutional regime. And there has to be latitude.
WELNA: But there are limits. Sweden's shoe quotas were rejected under international trade laws. Likewise, Senator Chris Van Hollen, a Maryland Democrat, says President Trump's imposing tariffs on Canada in the name of national security does not in his words meet the laugh test.
CHRIS VAN HOLLEN: I think there's a bipartisan consensus on Capitol Hill that the president is abusing the concept of national security.
WELNA: The problem, says another senator, Maine independent Angus King, is that that concept is so vague.
ANGUS KING: There needs to be a tighter definition of what actually constitutes a threat to national security. Otherwise it could be used as an all-purpose reason to justify any action whatsoever in any area.
WELNA: Who should define it?
KING: Congress. That's our responsibility.
WELNA: But the concept of national security was kicking around years before Congress even existed. Laura Donohue directs the Center on National Security and the Law at Georgetown University. National security, she says, has a long pedigree in American history.
LAURA DONOHUE: It actually predates the Constitution. It was back in the founders' diaries and comments and discussions at the time. So the concept of national security isn't new. The national security state - that's new. That is different.
WELNA: The national security state rose out of the Cold War with the 1947 National Security Act, which created everything from the CIA to the National Security Council. Expanding with it was the notion of what constitutes national security.
MARYAM JAMSHIDI: National security is basically whatever the government says it is.
WELNA: That's one more law professor, New York University's Maryam Jamshidi. Since the 9/11 attacks, there has been what she calls terrorism exceptionalism under which both the courts and the general public have acquiesced to ever-broader claims of national security.
JAMSHIDI: If it's a national security issue from the government's perspective, then many individual regular citizens are willing to buy into that as well because of course everyone wants to be safe.
WELNA: Through all this, there has still been no precise definition of the national security blanket that's been wrapped around so many official actions. It's like pornography, says South Carolina Republican Senator Lindsey Graham. You'll know it when you see it. David Welna, NPR News, Washington.
(SOUNDBITE OF ALESSO'S "DESTINATIONS")