President Donald Trump said he will announce his most sweeping economic measure yet Thursday, reciprocal tariffs that Trump argues would level the playing field for the U.S. in global trade and would instantly become the hallmark economic policy of his nascent second term, though economists project they would increase inflation this year.

Donald Trump's trade advisers on Wednesday were working on plans for the reciprocal tariffs the U.S. president has vowed to impose on every country that charges duties on U.S. imports, ratcheting up fears of a widening global trade war and threatening to accelerate U.