Trump’s new executive order will let more Americans invest in bitcoin for their retirement. Supporters tout higher returns, critics warn of more risk.

Millions of U.S. tax dollars have gone to China since 2011 to study the retirement and aging of its population.

The warning comes as a federal appeals court hears arguments on the legality of his tariff policy. Trump added that if the court were to rule against him, “they should have done so LONG AGO,” claiming ...