U-S President Barack Obama is defending the potential costs of health care reform. In an address to Congress last night, he estimated the changes he wants would cost about 900 (b) billion dollars over a decade. Obama says that's still less than the costs of the wars in Iraq and Afghanistan and ``less than the tax cuts for the wealthiest few Americans'' passed during the Bush administration. Health care has become the issue for Obama, just nine months after he took office amid enormous expectations at home and abroad.