Sacrosanct tax breaks, including deductions on mortgage interest, remain on the table just weeks before the deficit commission issues recommendations on policies to pare back with the aim of balancing the budget by 2015. The tax benefits are hugely popular with the public but they have drawn the panel's focus, in part because the White House has said these and other breaks cost the government about $1 trillion a year. At stake, in addition to the mortgage-interest deductions, are child tax credits and the ability of employees to pay their portion of their health-insurance tab with pretax dollars. Commission officials...