WASHINGTON — President Trump is increasingly blurring the line between America’s national and economic security, enabling him to harness powerful tools meant to punish the world’s worst global actors and redirect them at nearly every trading partner, including Mexico, Japan, China and Europe.

Over a few weeks, Mr. Trump has declared European and Japanese cars, Chinese telecom equipment and Mexican immigrants national security threats. Those declarations have given the president authority to use Cold War powers to inflict economic pain on countries through tariffs, government blacklists and other restrictions.

While previous administrations tried to deal with economic and security threats separately, Mr. Trump has deliberately mixed the two, viewing another country’s trade practices as dangerous to the United States as its military abilities.

It is a view he has espoused since the 2016 campaign trail, where he pushed his “America First” agenda and vowed to protect companies that he believed were on the losing end of global trade. Once in office, Mr. Trump immediately pulled the United States out of the multinational Trans-Pacific Partnership and initiated investigations into imported goods, like washing machines and solar panels, that he believed were flooding the American market.