The U.S. Treasury Department is set to maintain elevated sales of long-term debt to finance the government’s widening budget deficit, with new issuance projected to top $1 trillion for a second-straight year. A heightened supply of Treasury securities follows tax cuts and government spending increases implemented under the current administration. That’s darkening a fiscal outlook already made worrisome by rising entitlement-program expenses and higher costs to service America’s nearly $16 trillion in debt.