President Donald Trump’s plan to refill the US’s emergency crude storage system — “right to the top,” in his words — would help protect against future oil-price shocks. But it’s easier said than done.

Oil futures ended lower on Tuesday as traders weighed prospects for crude supplies after President Donald Trump vowed to boost already record U.S. crude output, threatened to implement a steep tariff ...

Oil futures headed lower Tuesday as traders weighed President Donald Trump’s vow to boost already record U.S. crude output ...