Long-threatened tariffs from U.S. President Donald Trump have plunged the country into trade wars abroad — all while on-again, off-again new levies continue to escalate uncertainty.

President Donald Trump, in his first Oval Office meeting with new Canadian Prime Minister Mark Carney, said there was nothing Carney could say to him Tuesday that would convince the president to reduce tariffs on Canadian goods.

The Trump administration has made moves to ease tariff tensions with China, but the situation remains uncertain in the longterm.