There's nothing like a housing crisis to inspire moral ambivalence. In a recent survey conducted by the Pew Research Center, more than a third of respondents said walking away from a mortgage is acceptable in certain situations. While a solid majority (59 percent) believes that so-called "strategic defaults" are wrong, an alarming number of underwater mortgages in the U.S. appear to be changing the terms of the debate. In July, lenders foreclosed on 93,000 properties, the second-highest monthly total since records began being compiled in 2005. According to the survey, approximately one-in-five homeowners are currently underwater -- that is, their mortgage debt exceeds their home value. As of the first quarter of 2010, 14 million borrowers were underwater, with another 6 million expected to follow in the months to come.