WASHINGTON—The Federal Reserve during Jerome Powell’s second term as chair will have an important role to play over the longer term to ensure that inflation does not become “endemic,” Treasury Secretary Janet Yellen told CNBC on Monday. Yellen said she believed Powell’s nomination and that of Lael Brainard as vice chair would win broad support in Congress and that she was confident in their ability “to make good judgments” on balancing the Fed’s dual mandates of maintaining maximum employment and price stability. “I think we do have to be concerned about inflation. It’s reached the levels that concern most Americans who are seeing it and their pocketbook when they go to the store to buy food or to fill up their cars,” said Yellen, who chaired the Fed from 2014 to 2018. She adding she believes that it is due to a supply-demand imbalance and economic bottlenecks that need to …