President Obama may propose a plan to allow homeowners with government-backed mortgages to refinance at today’s lower interest rates of about 4 percent. The move could save homeowners as much as $85 billion each year and would free up money that they could then spend elsewhere. Homes with government-backed mortgages lost 5.9 percent of their value in the second quarter—the steepest drop since 2009. The proposal is likely, however, to face fierce resistance from Fannie Mae and Freddie Mac’s regulator and investors in government-backed mortgage bonds. The U.S. government has also consistently overestimated the number of people who will enroll in mortgage-assistance programs.