But some important voices are raising questions about whether widespread principal reductions are the answer. When he was asked about that in a news briefing Friday, Assistant Treasury Secretary Michael Barr didn’t rule out broader use of principal reductions. But he suggested that there would be a risk that such a program would change a lot of borrowers’ behavior. “Most people, most of the time, make their mortgage payments …even if they’re underwater,” Mr. Barr noted. “You have to be quite careful not to design a program that induces more people to walk away” or one that strikes people as unfair. How would principal reductions induce more people to walk away? Let’s say your neighbor, who hasn’t made any payments on his loan for months, gets a huge reduction in his loan balance. Meanwhile, you’ve been working three jobs and dining on cat food to pay your note each month. Your reward from the bank? Zilch.