Donald Trump doubles down on his tariff ideas before New York business leaders Yahoo FinanceTrump says Elon Musk has agreed to lead proposed government efficiency commission as ex-president unveils new economic plans CNNWhat new proposals did Trump make during his economic speech? ReutersTrump vows to cut business tax rate to 15%, create government efficiency commission led by Elon Musk Fox NewsTrump backs plan that would give Elon Musk broad role in U.S.