The Obama administration sat by last week as 12 Senate Democrats joined 39 Senate Republicans to block a vote on an amendment that would have allowed bankruptcy judges to modify troubled mortgages.

Senator Obama campaigned on the provision. And President Obama made its passage part of his antiforeclosure plan. It would have been a very useful prod to get lenders to rework bad loans rather than leaving the modification to a judge.

But when the time came to stand up to the banking lobbies and cajole yes votes from reluctant senators  the White House didn’t. When the measure failed, there wasn’t even a statement of regret.

Mr. Obama’s plan to keep struggling Americans in their homes now relies on lenders to voluntarily rework bad loans. The plan provides ample incentives, including payments to servicers who successfully modify loans and, in some cases, payments to mortgage investors who agree to modifications. Whether that will be enough remains to be seen.