Government subsidies to help Americans buy insurance under the health care overhaul may be vulnerable to fraud, a Treasury Department watchdog warned on Tuesday in the latest indication that troubles are far from over for President Barack Obama's signature legislation. The rollout of the law has been hurt by canceled policies and problems with the federal website used by people to enroll in health plans, causing political headaches for the White House and for Democrats in Congress. The new problems concern subsidies that are available to low- and medium-income people who buy insurance through state-based exchanges that opened in October.
