Underwater mortgages are depressing housing demand by creating blockages in the mortgage finance system. Families in trouble because of a loss of income can't make their monthly payments, refinance, or sell their homes. By coupling effective counseling with robust solutions for troubled homeowners-such as loan modifications, refinancing, and rental housing options-we can get on the road to economic recovery much faster, writes Peter Tatian in a commentary for U.S. News & World Report's Debate Club.